Wiring to starter

Tiny
CLINTON STOUTENBURGH
  • MEMBER
  • 1999 DODGE RAM
  • 5.9L
  • V8
  • 2WD
  • AUTOMATIC
  • 107,000 MILES
Starter will not turn. Jumper from starter relay through coil to pat and ground works. Remove ground jumper and put bat to coil no good. Replaced ignition switch no help. Rolled fak realy and stater relay no change, but discovered fan does not work either. Seems connection from ignition switch to relays is open. Where do I look?
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Friday, June 23rd, 2017 AT 1:25 PM

9 Replies

Tiny
CARADIODOC
  • EXPERT
Your description is real hard to understand. "Jumper from starter relay through coil to pat and ground works" The starter relay has four terminals. Which one did you jump from? What coil? What do you mean by "to pat and ground works"? I do not understand what "rolled fak realy and stater relay no change", means.

What are the exact symptoms? Do you have a test light and know how to use it? That may be more accurate in this type of problem than a digital voltmeter.
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Friday, June 23rd, 2017 AT 1:44 PM
Tiny
CLINTON STOUTENBURGH
  • MEMBER
I will cut a past from work the window here is hard to type into.
Turning the ignition switch to start lights the panel but no starter. TGE move the starter relay and jump from term 30 to term 87 and the truck starts. Relay tests good and rolled with trailer and fan relays with no change. Connect a jumper to term 86 on the relay and to term 85t (across the relay coil), plug the relay in and connect the 85 jumper to ground and touch the 86 jumper to the possitive battery term and the starter turns. Sounds like the ignition switch so I replaced it. No change but out of curiosity turned the ignition switch on and tied the heater fan. Fan did not work.
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Friday, June 23rd, 2017 AT 2:40 PM
Tiny
CARADIODOC
  • EXPERT
OH! I get it. I do not think the two things are related, but we should not discount that possibility totally. I have the same ignition switch in many of my vehicles, including the one I am sitting in right now. It has a common problem of one set of contacts becoming overheated, and that heat migrates out to the connector terminals and causes them to overheat. This can work the other way too. One of those terminals can overheat and that heat migrates into the switch and overheats the contacts. This happens most often to people who use the heater fan on the highest speed a lot, and turn the ignition switch on or off while leaving the fan switch on "high".

Look at your old switch to see if two adjacent terminals are black or discolored. If they are, the fix is to replace the switch, and those two terminals must be cut out of the connector body, (that is usually melted too), then the first four inches of those wires must be cut away. They will be hard from being overheated, and solder won't adhere to them. Splice in four inches of new wire of the same diameter, then crimp on two universal terminals. Solder them too, then plug them in individually. Only use heat-shrink tubing to seal the splices. Electrical tape will unravel into a gooey mess on a hot day.

This circuit feeds the heater fan, power windows, and radio. A clue to look for, if you have power windows and a cassette player in the radio, is the cassette mechanism may kick out when both power windows bottom out at the same time. The stalled window motors will draw higher current when they stop running. That higher current causes a bigger drop in voltage across the ignition switch, and the radio incorrectly interprets that as the ignition switch was turned off. In response, it kicks out the cassette player so the pinch rollers do not get a flat spot. The cassette player will kick in again when you release the window switches.

That heater fan/window part of the ignition switch is not part of the ignition system or starter system, so with those two overheated terminals, the engine will still run and the starter will still work. That does not mean there cannot be something else wrong with the ignition switch. The problem I just described is just the most common one.

For the starter system, you're way ahead of what most people would have been able to figure out. Jumping thirty and eighty seven jumps the contacts, and the starter cranked, as expected. Applying ground and twelve volts to the relay's coil proved the relay was okay. Now, you should be able to apply just one of them to see which circuit has the problem, but here is a different way to approach this that works with any starter relay. The relay splits the system into four distinct parts. You can test each part on one of those terminals with the relay removed.

As a side note, these tests are best done with an inexpensive test light. You can use a digital voltmeter, but they can give false indications with this type of problem. If there is a carbon track across a break in a wire, or just a single strand of wire remaining and the rest are corroded away, that is enough for a voltmeter to show voltage is there, but a test light needs current to operate, and you will not get enough current through those breaks. The test light will show the correct test result.

One terminal in the relay's socket will have twelve volts all the time. In your case, that is terminal thirty. Another will have twelve volts only when a helper turns the ignition switch to the "crank" position. That's terminal eighty six.

Now move the test light's ground clip to the battery's positive post so we can test for a good ground circuit. Probe the two remaining terminals, and the test light should light up. The middle terminal on Chrysler relays is not used. Terminal eighty seven goes to the starter solenoid, then to ground. We know that circuit is okay because you had it cranking from the relay. Terminal eighty five is the ground for the relay's coil, but that is the circuit where Chrysler puts the neutral safety switch. Some manufacturers, including GM, put the neutral safety switch in the circuit coming from the ignition switch.

You are gong to find one of those two circuits is not working, and we already know thirty and eighty seven are okay. That leaves eighty five or eighty six as not working.

Next, your truck still uses the common sense neutral safety switch that Chrysler used since the early 1960's. It has three wires. The two outer wires get connected together to turn on the back-up lights. The middle wire gets grounded in "park" and "neutral" to ground the starter relay's coil. If I was a betting boy, my bet is for the neutral safety switch. Next would be someone had the plug off, and it did not get put back on tight.
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Friday, June 23rd, 2017 AT 4:22 PM
Tiny
CLINTON STOUTENBURGH
  • MEMBER
Thank you. I just go there on my own and am looking at the picture in my manual. I jumped term eighty five on the relay to ground and turned the key and it started. I had read more closely the labeling on the wiring diagram. Four years in power production in the USAF (million years ago) and forty as com tech with the phone company taught me to read and I grew up working on cars, not so much the newer ones. A grandson will be up in the morning to help lift the truck and crawl under. If I have to replace it, how much oil will I loose?
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Friday, June 23rd, 2017 AT 5:55 PM
Tiny
CLINTON STOUTENBURGH
  • MEMBER
By the way, replacing the ignition switch was not a total waste, the old one was sloppy. And again thank you profusely.
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Friday, June 23rd, 2017 AT 5:58 PM
Tiny
CARADIODOC
  • EXPERT
Nothing, the switch is up high enough that no fluid will run out unless the truck is not level. It is in the left rear corner. If you buy a new one from the dealer, be sure it comes with a gasket. That is a stamped aluminum ring. The old one usually sticks to the old switch. It can be removed, but the cost is so low, it does not pay to hope it will seal on the new switch.
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Friday, June 23rd, 2017 AT 6:26 PM
Tiny
CLINTON STOUTENBURGH
  • MEMBER
Got it running, a rat tore up the wiring, but there is a connector hanging left rear of the transmission and check engine says "shift solenoid A electrical". Cannot find where the connector plugs in?
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Saturday, June 24th, 2017 AT 1:40 PM
Tiny
CARADIODOC
  • EXPERT
There are a couple different transmissions that were used. If that is a round 8-pin plug, the solenoid pack is right above the neutral safety switch.
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Saturday, June 24th, 2017 AT 7:26 PM
Tiny
CLINTON STOUTENBURGH
  • MEMBER
Thanks, got it plugged in and that code is gone. Output speed sensor code now but my son-in-law who plugged it in checked that wiring so I think I might need to replace that. It is cheap?
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Saturday, June 24th, 2017 AT 8:54 PM

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