It all worked, except the heat, ran calibration now, no heat or AC.

Tiny
RAYZOR
  • 1998 DODGE CARAVAN
  • 240,000 MILES

I have a 1998 Dodge Caravan. It was fine till I went to turn the heat on. There was no heat at all.

I ran the calibration test and got a code where the Rear Wiper LED flashed once, the intermittent LED flashed 4, 5 or 6 times. Of course the Rear Wiper LED flashes once before the other codes, 1-4, 1-5, 1-6

It seemed to me the code was saying there was a problem with the Evaporator probe (open or shorted).
I replaced the probe twice. Re-ran the calibration test again and got the same results.

I ran the cool down test and it failed. When it failed both the Rear Wiper and Intermittent LED's flashed at the same time.

Prior to all this everything worked, I live in Southern Florida, so don't need the heat often. I just randomly tried it. It used to work. Now none of it works. I need the AC!

The fan works fine, I can hear the blend doors moving during the calibration.

Is there a way to bypass the "codes" and get back to where I was before all this happened?

Ray

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Thursday, June 21st, 2012 AT 10:55 PM

13 Replies

Tiny
ASEMASTER6371
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Was there any issues prior to the calibration?

Roy

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Thursday, June 21st, 2012 AT 11:03 PM
Tiny
RAYZOR
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There was no heat, I did not need heat. I just stumbled on the fact it was not working. Ray

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Thursday, June 21st, 2012 AT 11:15 PM
Tiny
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Were all the lights blinking before you tried the calibration?

Roy

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Thursday, June 21st, 2012 AT 11:22 PM
Tiny
RAYZOR
  • MEMBER

Nothing was flashing, I only ran the calibration to get the heat working. This has occurred twice in the 12 years I have owned this van. In the past the calibration fixed it. Today is different.

Ray

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Thursday, June 21st, 2012 AT 11:24 PM
Tiny
RAYZOR
  • MEMBER

All the flashing that is happening now only started after the calibration.

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Thursday, June 21st, 2012 AT 11:25 PM
Tiny
RAYZOR
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Is there a way to kill the calibration codes and get back to where I only had "no heat". I don't really need the heat in Southern Florida.

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Thursday, June 21st, 2012 AT 11:27 PM
Tiny
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The reason for all my questions is background as you now have a failure and I do not think calibration is going to solve it.

Did you do the basics for no heat? Coolant, thermostat, heater core circulation. If all that is good, then we move to the inside for checking the blend door movement. Calibration should take place after the problem is found, repaired and verified.

Basics, basics.

Roy

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Thursday, June 21st, 2012 AT 11:27 PM
Tiny
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Hi guys. If you mean "no heat" as in it blows cold air, feel the heater hoses. They should be too hot to hold onto for very long. If they are not, suspect a plugged heater core. They can usually be cleared by running water from a garden hose through them.

If you mean "no heat" as in the system turns off, replace the computer. It is the entire bezel around the radio.

If the heater hoses are hot, the temperature blend door actuator could be broken or disconnected. There is a position sensor on it that would not change so that would fail the Actuator Calibration test.

The Cool Down test can be extremely frustrating to get it to pass even when everything is working correctly. My record is 20 attempts before it worked. You might find some useful information at the bottom of this page:

http://randysrepairshop.net/reprogramming-the-chrysler-hvac-computer.html

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Thursday, June 21st, 2012 AT 11:29 PM
Tiny
RAYZOR
  • MEMBER

I did check the coolant levels, they were fine. Nothing unusual at all, except for no heat.

I ran both the calibration and cool down. Both failed even after I replaced the evaporator probe.

I tried to kill the codes by disconnecting the battery for about 20 minutes. I now know the codes are stored somewhere.

Can I erase the codes?

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Thursday, June 21st, 2012 AT 11:37 PM
Tiny
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Do not disconnect the battery. THAT is why the HVAC Computer has to be recalibrated. It loses its memory.

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Friday, June 22nd, 2012 AT 1:01 AM
Tiny
RAYZOR
  • MEMBER

Ok, Is there a way to erase the codes to get back to where I was before all this started?

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Friday, June 22nd, 2012 AT 1:22 AM
Tiny
CARADIODOC
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The codes go away automatically when the tests have passed. You can do that too by disconnecting the battery but then you gotta start all over. The Actuator test always passes on the first try if everything is working correctly so to avoid having to do it over again, I don't like disconnecting the battery. It's the Cool Down test that gives all the trouble. Don't assume there's a problem simply because the test doesn't pass. I can't speak directly about the codes you're getting but I DO know getting that one to pass is very frustrating on '97 and '98 models. Don't overlook the value in doing that test right after driving a few minutes at highway speed.

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Friday, June 22nd, 2012 AT 1:46 AM
Tiny
RAYZOR
  • MEMBER

Thanks, I saw that on the site you referred me to. I will be back at it tomorrow. Thank you for your help. Ray

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Friday, June 22nd, 2012 AT 1:50 AM

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