Blower motor switch

Tiny
GARY PARLATO
  • MEMBER
  • 2002 DODGE CARAVAN
  • 3.3L
  • V6
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
On my van my blower motor switch works on all settings but the one before high. (In other words high works, number three works and number two works and number one works but not speed four) Replaced, blower motor resister, entire center console A/C control and fan switch panel and also blower motor relay and fuse. Even the dealer cannot figure it out.
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Thursday, May 4th, 2017 AT 1:58 PM

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Tiny
CARADIODOC
  • EXPERT
Your dealer did not put their electrical specialist on your van. This part of the circuit is very basic and easy to diagnose. Pull out the heater control so you can access the wires going to the fan speed switch. For these tests a test light will be more accurate than a digital voltmeter. Use it to check for voltage on all of the wires at the switch. You should be able to poke the probe into the connector alongside the terminals.

You should always find 0.0 volts on the black/orange wire. That is the ground wire for the motor, and that has to be okay because some of the speeds work properly.

Next, you should find 12.0 volts on all the other wires except the one that is switched on. If you switch to the highest speed, you will find the dark blue/gray wire has dropped to 0.0 volts, and the motor will run on the highest speed. Switch it to "off", then check the voltages on the other four wires. You should find 12 volts on all of the dark blue wires. What I am interested in is the voltage you find on the dark blue white wire.
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Thursday, May 4th, 2017 AT 4:22 PM
Tiny
GARY PARLATO
  • MEMBER
Thank you I will test all of this tomorrow and let you know what I found. Thank you very much for the advise. My dealer does not seem to be qualified to find some problems but more then qualified to charge you for their time.
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Thursday, May 4th, 2017 AT 7:14 PM
Tiny
GARY PARLATO
  • MEMBER
With fan switch turn to the lowest position to the left we have power to the large blue wire with the gray stripe, no power to the blue wire with the white stripe, black wire with orange stripe has no power, small blue wire with light gray stripe has no power, blue wire with orange stripe barely lights the test light, light blue wire with the red stripe has power. Now switched fan switch to first position to the right, has power on large blue wire with gray stripe, no power on blue wire with white stripe, no power on small blue wire which looks like gray stripe, no power to blue wire with orange stripe, blue wire with red stripe barely lights the test light. Now I switched the fan switch to the next position to the right only power I have is on the large blue wire with the gray stripe which barely light the test light. Now I switch the fan to the right which is the speed that does not work and all the wires except the black wire with the orange stripe and the blue wire with white stripe light brightly. Now I switched the fan to the full right high position and no wires light. The blue wire with the white stripe never lights up in any position.
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Friday, May 5th, 2017 AT 8:24 AM
Tiny
CARADIODOC
  • EXPERT
My head was spinning until I read your last sentence. That is what I expected you to find, but I wanted to verify it and not overlook something stupid. That one dead circuit could be caused by a bad connection inside the resistor assembly, but you replaced that already. At this point the solution is unbelievably simple, ... Once we locate the cause. You have a wire between the resistor and the switch, with a terminal on each end. That's it.

Here's the list of things to consider, and I purposely complicated it to make it look harder than it needs to be so you think I'm putting some effort into this! These are in order of likelihood.

1. The terminal at either end of the wire is "spread". That means it was stretched from poking a test probe into it too far, or it became badly overheated. Often the fan motor will start to run when you wiggle the connector. Look for a melted area in the plastic connector body.

2. The terminal became overheated, the plastic connector body melted or deformed, and the locking finger became weak and let the terminal back out. All the other terminals are pulled up to the resistor or switch and plugged into them solidly, except for that one. You'll see the terminal not poked in far enough, and you may be able to pull that wire all the way out.

3. The wire is not crimped to the terminal properly. To be specific, the insulation wasn't stripped back far enough before the terminal was installed. That's a manufacturing problem and would have shown up before now. Or, it became a problem after someone replaced a blackened terminal.

4. That one wire is cut.

If you can't find the cause visually, use your test light and try to stick the probe on the resistor terminal corresponding to the dead wire, just under the front of the connector. Leave the switch in the "off" position. When you find 12 volts there, test next on the back side of the connector body, right on the terminal. If there's no 12 volts there, that terminal is not making contact with the terminal on the resistor. If you DO find 12 volts there, do those same tests on the switch end of the wire.

As a point of interest, the reason I asked you to use a test light is they draw current from the circuit to work. When that happens, some of the voltage, (electrical pressure), is dropped across the resistor, and the rest is dropped across the test light. If 8 volts is dropped a resistor, that leaves only four volts to run the test light, and that's why it's on, but dim. A voltmeter doesn't draw current from the circuit. It simply measures the electrical pressure, just like a pressure gauge measures pressure in a compressed air line, but no air actually flows through the gauge. All you need is the tiniest of a strand of wire, or piece of moist corrosion, and enough voltage can sneak through to show up on the voltmeter. That would incorrectly show the circuit is okay up to that point, but in fact, there's no way you could get enough current to flow through that bad connection to run a motor. Using the expensive voltmeter has lead a real lot of experienced people down the wrong path when a cheap test light would have given the more accurate result.
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Friday, May 5th, 2017 AT 5:21 PM
Tiny
GARY PARLATO
  • MEMBER
OK thanks for this information. I do have other new connectors I could install. Also have new other resistor blocks. Now after this weekend I will start the tests you just have mentioned here. I can't thank you enough for this valuable information. So let me get this right. The blue wire with the white stripe must pickup it's voltage from the connector at the resistor block? I think you are right and once the blue wire with the white stripe gets voltage to it, it will all work fine. Now since you have nothing else to do (HA Ha) here is another thing the dealers can't find even with a smoke test ( I have my own smoke tester). This is a evav code of 0441 (purge flow). I have replaces the purge solenoid, vent valve, charcoal canisters, every single vacuum line on the vehicle (lots of fun to do), gas cap, fuel sensor. About the only thing I haven't replaced is the leak detection pump. This code comes on and I reset it and may not come back on for two to three weeks again but then pops up again. Reset it again and then a month later it shows up again. I am disabled in a power chair so I spend all my time working on this dodge piece of junk. Wouldn't be happy if I had a van that actually had nothing wrong with it. Life would be boring! Again thank you.
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Friday, May 5th, 2017 AT 8:09 PM
Tiny
CARADIODOC
  • EXPERT
First let me address the fan motor. Sorry if I'm talking beneath your understanding of electrical theory.

For a circuit to work, current has to have a "complete path" to flow from the battery positive terminal, through all the wires, connectors and "loads", meaning a light bulb, motor, heating element, etc, then back to the battery. Anything that breaks that current path stops the flow of current, and the circuit stops working. We're looking for an unintended break that is causing the fan to not run, but our job is a real lot easier because the motor DOES run on some speeds. That proves 99 percent of the circuit is okay.

What I'm leading up to is intended break in the circuit. That is the switch. Where this becomes unnecessarily-complicated is when they move that switch to an uncommon place in the circuit. We normally think of turning the light switch on in your house, and that applies voltage to the bulb, and current starts to flow. In truth, that switch can be anywhere in the circuit and do the same thing. That has been standard for decades with dome light switches in cars. The 12 volts is always applied to the bulb, but current flow is stopped by breaking the ground side of the circuit with the switch. That is what they're doing with your fan motor, and that is backward from normal thinking and how it was done years ago. There's no advantage or disadvantage to doing it either way. It just requires knowing what to expect for voltage readings during testing.

For your motor, current goes to the motor first, then finds a path through the one resistor in the assembly that you've selected, through that part of the switch, then back to the battery. The resistor limits current flow which reduces motor speed. We totally skipped past one step, testing for voltage at the motor, because we know that part is okay. We need to ground the other side of the motor to make it run, and we do that with the switch. You have five switches built into the assembly, and each one is connected with a wire to its own resistor. Each of four of those switches can successfully ground the motor and make it run. We're looking at the one that doesn't do that due to an unintended break. Where it sounds like it gets complicated is from all the test points I listed. You may have faster results from just looking at the terminals to see which one is not making good contact. To compare this to water flow in a garden hose, if flow has stopped, you could take a pile of pressure tests all along the hose to find where the blockage is, or you could simply look for the kink in the hose.
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Friday, May 5th, 2017 AT 9:32 PM
Tiny
GARY PARLATO
  • MEMBER
OK I understand everything you mention about current flow. I am sure I will find the problem when I start checking it all out on Monday. You are very knowledgeable concerning this mater, more so then any one at any of the dealers I have listened to before. Sometimes I believe the technicians at dealers are nothing more then parts re-placers. You have to understand ohms law and how something works before you can honestly repair it. Some times I think technicians rely to much on their equipment rather common sense. No one these days seems to what to learn anymore.
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Friday, May 5th, 2017 AT 11:30 PM
Tiny
KEN
  • ADMIN
Please let us know what happens.

Cheers, Ken
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Monday, May 8th, 2017 AT 5:07 PM
Tiny
GARY PARLATO
  • MEMBER
Sorry I didn't get back with you sooner. Spent two days in the hospital for some tests. Well nothing was wrong with the blower motor switch connector or the connector on the resistor block or the terminals. I then checked the continuity on the blue wire with the white stripe. No continuity on the wire from one end of the wire to the next. Somehow the wire was broken. I cut out the blue wire with the white stripe at both the blower motor switch connector and the resistor block connector. Soldered a new wire in (same gauge wire) and heat shrinked the wire. Presto everything works great now for the last two days. Can't thank you enough for your help. Here is something that will blow your mind. Check light came on with a 0441 code. On the dodge van you just have to turn the ignition switch on three times and it will read the code on the digital trip meter. But here is the weird thing. With the check light on, my code scanner doesn't read any code malfunctions. The scanner can't erase the code since the scanner doesn't see a check light malfunction. Checked the code scanner by loosening the gas cap and the scanner reads a 0455 code. Disconnected the purge solenoid valve and it reads that code to. But my scanner never sees a code like the 0441 code malfunction. It is weird to me and my code scanner wasn't cheap cost $250.00. Thanks again for all your help!
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Sunday, May 14th, 2017 AT 1:30 PM
Tiny
CARADIODOC
  • EXPERT
Yippee! One in a row! Of all the possibilities I listed, a cut wire would have been my last guess.

P0441 - Evaporative Emission Control System Incorrect Purge Flow

Don't know why that would not show up on every code reader.
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Sunday, May 14th, 2017 AT 5:50 PM
Tiny
GARY PARLATO
  • MEMBER
I borrowed my friends foxwell code reader and tested it on my dodge van today just to see if it saw the 0441 code. Guess what! The foxwell scanner said no codes found! It also couldn't erase the code because it never detected it. I think it is a problem with the ECM. Maybe it is a Glitch in the controller. Took off both charcoal canisters today. Checked for pellets maybe loose and also checked to see if canisters were clogged. Checked for cracks in the canisters. Everything looked good. Also vacuum tested the hose from the canister to the purge solenoid and no leak on the hose. Hose also was clear from any clog's. Now I installed another purge solenoid and reset the check light by disconnecting the battery. Restarted the car after 5 minutes and check light was off. Now I will drive it and see if in a week or so the check light comes back on with the 0441 code. I did see on you tube that a man had the same problem so he replaced the ecm and had it flashed by the dealer. Hasn't drove it very far so don't know yet if it fixed his problem. My dodge caravan is a 2002 and I have 130,000 miles on it. It looks like brand new, drives like new and runs like new. This is how I keep it. The problem is it is 16 years old and only God knows how much deterioration the wires in the system have on them. Well I am off tomorrow to rebuild the alternator again. Bearing making a lot of noise and alternator serpentine pulley bad again and making noise. If you need something to work on all the time buy a Chrysler product, quit your job because you need all the time you can get to keep it running. Thanks again for all your help. I have the factory dodge 2002 complete service manual for my van. It is 2,400 pages long and I still can't figure some things out. It is amazing the van runs with all the stuff that can go wrong. I will let you know if the check light comes on again. Without your help I may never have fixed the blower switch problem. Almost forgot, have to evacuate the air conditioner again and install a new dryer. With this vehicle I wouldn't have time to have a job. Thanks again!
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Monday, May 15th, 2017 AT 1:32 AM
Tiny
CARADIODOC
  • EXPERT
You must not have owned many other vehicles. Since back in the '50s, Chrysler has always been the world leader in developing innovations that directly benefited car owners. That includes anti-lock brakes, (1969), AC generator, (Chrysler copyrighted the term "alternator"), (1960), lock-up torque converter, (1977), electronic voltage regulator, (1970), fully electronic ignition, (Dodge: 1972, Chrysler / Plymouth: 1973), computer-controlled ignition system, (1976), domestic front-wheel-drive, (1978), air bags, (late '80s), computer-controlled automatic transmission, (1989).... They even had time delay lights to help you see where to put the ignition key, in the mid '60s. Today that can only be done with a Body Computer.

In contrast, GM is the leading innovator in developing customer-unfriendly business practices. This started with their very nice AC generator with the built-in voltage regulator, (1972), and their first electronic ignition system, the "High Energy Ignition System, (HEI)", (1975) that were self-contained assemblies. Very nice for mechanics who didn't understand how they worked, and they could just pop in a whole new system, but very expensive for car owners who had to buy the whole system instead of the one failed part. Opinions vary as to whether this is an advantage or not. First manufacturer to stop allowing us to buy their radio service manuals so they could lock up all that lucrative repair business for their two grossly-over-priced authorized repair centers. Only manufacturer to have a 100 percent failure rate of their CD players over a ten-year period, (1990s). Only manufacturer to have a nearly 100 percent failure of their rack and pinion steering gears within the warranty period, and their solution was a cheap way out in hopes it would hold up just long enough to get the car out of warranty; then it was the owner's problem to fix it properly. First manufacturer to design computers that if replaced, must come from the dealer and must be programmed by them, at considerable cost. First to build the Body Computer into the radio so the radio can't be replaced with an aftermarket unit. Only manufacturer to build into their scanners the option to electronically "lock" all of the dozens of the car's computers to the radio, so if the radio / Body Computer needs to be replaced, every other computer on the vehicle must also be replaced. That can be done by any disgruntled GM mechanic, and you'll never know it, ... Until the radio fails. That "lock" procedure can't be undone.

I won't even be able to see straight if I start in on all the devious stuff Ford has pulled, from non-alignable cars that couldn't help but tear up tires in 15,000 miles, steering parts that separate, leading to loss of control and crashes, in as little as 15,000 miles, and my favorite, two computers, the instrument cluster, which is the master computer, and the "FEM", "front electronic module", required to blow the horn! Typical repair for a dead horn is $800.00.

As disgruntled as you are with fixing your Chryslers, I feel the same way with the Two Fords I've owned, and the four I'm always working on for my friends and relatives. No one can complain about fit and finish, ride quality, handling, and comfort, but with all the progress we've seen in the last 40 years, we should be able to change the oil a couple of times per year, inspect the brakes and suspension systems every other year, and add gas as needed. Instead, many of my former students who owned GM cars thought it was normal to have an $800.00 repair bill every six months. Well, normal for YOU maybe, but not for me.

I recently retired my '88 Grand Caravan due to severe rust, but I hadn't changed the oil in over 15 years and 150,000 miles. (That is not a recommendation for anyone)! The transmission filter was replaced once, at 85,000 miles, and I dragged a tandem axle enclosed trailer with it to car show swap meets for 15 years. That trailer is bigger and heavier than the van, and I never needed the trailer brakes. My "new" daily driver is a simple '94 Grand Voyager. In the year and a half I've been driving it, I changed the oil twice, replaced two tires, and repaired two amplified speakers. Replaced the very uncomplicated instrument cluster so I could have a tach. Oh, and I did have to replace a rusted steel brake line, but that's typical up here in Wisconsin where they throw a pound of salt on an ounce of snow.

The biggest true progress I've seen is cars today are seriously cleaner, but that is due to careful monitoring by the Engine Computer. The technology to achieve that showed up on every car and light truck in 1996, but no other computers are needed or are involved with that task. All of the technological advancements since then involve complicating things like power windows, heater systems, and the starter system. People buy cars today according to the number of cup holders, whether it has butt-warming seats, interior lights that fade out gradually, (that's very important, you know), motorized doors, and all the other toys and gimmicks the designers tell us we need. Seems few of us stop to think about those past buying decisions when we're complaining about the repair bills. I wouldn't even grump about most of the technology as long as I could still drive the car safely after any of those systems failed. If I can unlock and open a door, turn the steering wheel, get the stupid child-proof, politician-approved shifter out of "park", and get the engine started, I'm happy. I'm REALLY happy in winter when the dash blows warm air on my feet! I really don't mind pushing a slide lever if I'm feeling especially warm or cold. That lever causes an awfully lot less trouble than a push-button telling a computer what you hope it will do. You might have another toy to play with while you're driving, but I can't guarantee that computer will make you comfortable during that drive.

Since the day my '80 Volare was new, it consistently gets 28.3 mpg on the highway. That's a 4,000 pound car with chromed steel bumpers. I'm quite happy that today's cars are cleaner, but with all of our technology, shouldn't they be getting better fuel mileage than one that weighs twice as much, from 37 years ago? Everything else, we're told, is improved. Why not fuel mileage?

By the way, I spent 90 bucks for oil changes, air filters, wiper blades, and other repairs on that car in its first 32,000 miles / 25 years. Today 90 bucks get your name mentioned at the service desk.

So to sum up this wonderful story, I'm sorry you're always having to fix something, but your job should be easier now that you've met us wizards who are here to help you. As I used to tell my students, "you're welcome to like any brand of car you want to, just don't tell me yours is better than mine, ... Unless you can tell me why. You may not care in the least about the things I find important. That can include ease of access for serviceability, parts interchangeability, parts availability, ease of accessing service information, the need to add an unnecessarily-complicated computer to every circuit and system that never needed a computer before, and things like that. In my next lifetime, I'm going to be the CEO of a major car manufacturer. My goal will be to base all design and marketing decisions on the best interest of the car owners, just like politicians SAY they have our best interest at heart.

Hope you have better luck with whatever you're driving, but remember we're here when you need us.
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Monday, May 15th, 2017 AT 5:21 PM

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