Chrysler Repair/Starter Relay Circuit: '94=96 LH body
QUESTION: Hi Roland. I had the orientation of the starter relay wrong. Yes the red wire is on pin B and is hot with ign. switch on and off. It also has a Green/Black wire on it. Pin D has a light green wire(assume to solonoid) on it and has no voltage on it with ign. switch on or ff. I can start the car with the relay out by jumping pin B to pin D with the ignition on(which I assume is bypassing the P/N switch). Pin C has no voltage and 0 ohms resistance when tested with battery ground. Pin A must be the problem as I have no voltage with the relay out and the positive prob in the socket and the neg. prob grounded at the battery with the switch on. Does the yellow wire come directly from the ign. switch to Pin B and pin 8 on the TCM or run from the ign. switch through the TCM back to Pin B. I had put a new ign. switch in about 6 months ago and maybe it has gone bad , although if it were bad why would I be able to start the car by jumping Pin B to Pin D with the relay out and the switch on.
ANSWER: The ignition switch has a number of switch sections in it. The Yellow wire is in a section which sends 12V to the yellow wire when the key is in the start position. With the key in the run position (what you describe as "on") it sends voltage to the radio, turn signals, and wipers. There is a different section of the switch which powers up the engine module in the run and start positions and that is why the engine will run when you jump the starter relay socket with the switch in the run position.
The yellow wire goes from the ignition switch to a splice inside the engine compartment where it is tied into the yellow wires that go to the relay pin A and the TCM pin 8, So if you don't get voltage at A in the start position, then you need to verify whether the yellow wire at the ignition switch is indeed getting 12v in the start position or not. If not, then the switch is bad (trying spraying it with electrical contact cleaner). If so, then there is a problem in the wire to splice to pin A connection.
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QUESTION: I went back and retested all the pins in the start, run and off positions with the relay out for voltage as well as resistance with the car in park and also in drive gear. The results are as follows:
In park for pin A: 12 Volt in start, 0 volts run position, 0 volts off position. 0 ohms resistance start, 30 ohms resistance in run and 60 ohms resistance in off position. In drive gear for Pin A with ignition in run 0 volts, 30 ohms resistance.
In park for Pin B: 12 volts in start, run and off positions. 0 resistance in start, run and off positions. In drive gear for Pin B with ignition in run 12 volts, 0 ohms resistance.
In park for Pin C: 0 volts start, run, and off position. 0 ohms resistance start, 0 ohms run, 5.5 ohms resistance in off. In drive gear for Pin C: 0 volts, 5.5 ohms resistance run.
In park for pin D: 0 volts start, run and off. 0 resistance start, run and off
In drive gear for Pin D: 0 volts run and off. Resistance 0 for run, off
I don't know whether this will help interms of isolating the problem.
ANSWER: Hi Bob,
I don't see any problem with the voltages. I don't see any problems with resistances either though I don't have the exact values of resistance that would be expected.
With the relay in the socket, does it click when a helper tries the start position?
If so that is correct, if not then try substituting another relay with the same part number from the box,
if the relay clicks, then just to be sure go to the starter motor and measure for voltage at the blue wire on the solenoid switch when the key is turned to start by a helper. Do you get 12v there?
If so, then the solenoid switch on the starter should also click loudly. Does it?
Let me know.
About 9 days ago you said the lights of the PRNDL were all lit up, which is clearly not correct. Is it still doing that? Did you check the wires from the multi-pin plug as I described? Until that issue is resolved we may not get starter action, if the TCM doesn't see the gear to be in P or N. I just can't be sure but it is an issue nonetheless that has to be resolved. Did you say that you replaced the PRNDL in the transmission? And you did say that you put in a used TCM, but was the all light on like that with the old TCN? If not, do you have the old TCM and could you try putting it back in place to see if the light problem is still there?
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QUESTION: Hi Roland,
Sorry about the delay in getting back to you, but I had to test out a few things.
I have replaced the PRND3L switch. There is no solenoid click with the old relay or by replacing the relay with another of the same part number.
The PRNDL lights became all lit up after I replaced the switch. Prior to the PRNDL switch replacement only the R was lit when in P, but the D would light appropriately when selecting it. I can't recall whether 3 or L would light appropriately. The car was in 1st gear limp mode and would not shift into any other gear whether using the shifter or by itself in D before I replaced the PRNDL switch.. The speedometer was also registering 70 mph in P and would go back to 0 when going from P to D. I then replaced the speed sensor output which corrected the speedometer issue after I had replaced the PRNDL switch.
After the PRNDL switch replacement the car would then start in third gear using the jumper pin B to D socket starter relay out. If I reset the TCM by disconnecting the battery for a few minutes I could get the car to shift properly, but not every time. I then replaced the TCM and it has shifted properly ever since and I have put about 200 miles on the car since replacing the TCM. I ran key codes before and after replacing the TCM and it only showed 12 and 55 each time. When I shift the car from P into R or D these will light by them self. The 3 and L do not light up at all. When the car is placed in L or 3 the car shifts as if it is in D. I can't make the car stay in L or 3 by selecting these gears.
I haven checked the multi pin plug going to the PRNDL switch as I presently can't get to it, but will do this in the near future as this seems the likely culprit.
As to the continuity check between black/light green on Pin C connection at the starter relay socket to pin 30 of the PCM, and the brown/yellow at pin 41 of the TCM plug(where is this coming from)should this be done with the switch on?
There is either an issue with the PRNDL switch or its wiring to the PCM/TCM/starter rely or the TCM may not be interpreting what it 'sees' from the switch, or even the digital bus connecting the tcm to the shift position indicator erroneous lights on the cluster (and also to the pcm) may be impaired. Only by checking the pins of the manual valve lever position sensor and the wires between its plug and the tcm will you be able to sort that out.
If you want to verify that the no start is related to this, try grounding the pin 30 of the pcm plug (use a pin to pierce the black/light green wire at that pin and then ground the pin. That should allow you to use the starter in any gear position so be careful to not leave it this way. But at least that will prove that the problem is as I described it above. If there were no problem that wire would be grounded by the transmission range switch when it is in P or N. The brown/yellow at pin 41 of the TCM plug is in fact connected to that same grounding switch inside the transmission that you replaced. These groundings occur without regard to the ignition switch being on of off. But only if these wires are grounding will the starter relay close and the starter fire up.