QuestionQUESTION: I followed the troubleshooting section in my Haynes manual. All fuses in pcm and distribution box (inside car left dash end) are all good. There is continuity on ignition sw between on and start when ign is turned to start. Also checked with ignition connected and get 12v on yellow wire when I turn to start. I hear nothing from the starter solenoid. I then checked pin 86 on the starter relay with ign on and no 12v there. do get 12v at pin 86 on the asd relay. They should be the same according to the manual. how do I check the run wire from ignition sw to starter and how do I trace 12v from ignition sw to pin 86 on the starter relay. Of course the Hanes manual does not show the complete wiring diagram. I was a front line mechanic for AMC for 10 yrs. and this one has me stumped. Thanks in advance if you can come up with a solution. Don
ANSWER: Hi Don,
I added some more details:
The pin numbers at the starter relay as shown in the Haynes are different from the numbering shown in the Chrysler shop manual so maybe the best way to describe the circuit is via the wire colors at various pins. I will assume that you have an automatic transmission, otherwise let me know.
The ASD and the starter relay don't get their main power from the same fuse (fuse 8 supplies the starter, fuse 5 supplies the ASD).
The yellow wire from the ignition switch's start position goes to a disconnect where its color become yellow/orange and thence to a pin 81 at the relay which is attached to one end of the relay actuation coil. The other end of that coil has a black/white wire (at pin 83) that is routed to the transmission range sensor (it changes to black/light blue by the time it gets to pin 5 of the 10-pin plug at the transmission range switch) which in the P or N position should ground that wire which then completes the actuation coil and thus closes the relay whenever you turn to start with the key. You should hear the relay click if the black/white wire has been grounded at the range switch.
If you don't have 12v at the yellow/orange wire at the relay, then the yellow wire to the disconnect or the yellow/orange wire from the disconnect to the relay is 'open'. The disconnect is 16 pins, black in color, and is located under the dash virtually a part of the bcm/junction block assembly. The specific pin there is #8. So check the continuity between the ignition switch and the relay pin socket, and if that is good then when try 'start'; 12v should appear at the relay on what the Chrysler manual labels as pin 81 (rather than 86 as shown in the Haynes).
Then check that the black/white wire at pin 83 of the relay socket is grounded via the P/N switch. Once the relay closes, if you have 12v on the red wire (which is on pin 87 and comes from fuse 8 all the time) at what Chrysler shows as pin 87, then the closing of the relay puts 12v out on the brown wire (pin 79) that goes to the solenoid switch.
In the starter relay socket the pins are as follows:
rear 83, front 81, inboard 87, outboard 79.
That is the starter motor circuit. Did you try switching out the relay with another one in the box?
By the way we enjoyed a couple of AMC Rambler sedans in the 60's-80's.
Please read the PS below and then respond to it.
Thanks,
Roland
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QUESTION: Hi Roland, I connected a wire to pin 81 and plugged the relay back in. remarkably I had I've (only when the ignition switch is on). According to the Haynes manual that's the way it should be. Unplugged the relay, took the wire off and checked pin 81 in the socket. I had nothing there with key on or off. Also tried the ignition start and still nothing there. It looks to me like pin 81 is getting the 12 V from pin 87 through the relay. I looked up this relay functionality and if pin 87A (center) gets 12 V to it then pin87 connects to 79 causing the starter solenoid to pull in. However I don't have a wire connected to the center pin (frustrating at best). in response to your question, yes I have change out two other relays with the starter relay and it had no effect. Is there a fusible link somewhere in this start circuit? I would think not since it uses fuse number eight. Any other ideas you may have would be greatly appreciated. Oh by the way I have worked on some ramblers in my life LOL
ANSWER: Hi Don,
I am confused about what your first sentence means:" I connected a wire to pin 81 and plugged the relay back in. remarkably I had I've (only when the ignition switch is on)."
What is "I've"? amd which position is the ignition switch in when get "I've"?
Pin 81 should be 12v only when the key is in the 'start' position.
I don't have am idea what 87a is connected to because it isn't shown to be involved according to the wiring diagram. I suppose it could be connected to 87, but I still don't see how pin 81 would get 12v from pin 87 or 87a unless there is a short in socket or a short in the relay itself.
The only fusible link is from the starter solenoid switch to the generator which is the fat charging lead wire back to the battery from the generator.
You have to get 12v to pin 81 from the ignition switch in order to close the starter relay.
Have you had any success tracing to the disconnect and from there to the relay socket?
Anyhow, what should the first sentence be?
If you would do a rating and nomination I would be most appreciative.
Roland
---------- FOLLOW-UP ----------
QUESTION: Hi Don,
I am confused about what your first sentence means:" I connected a wire to pin 81 and plugged the relay back in. remarkably I had I've (only when the ignition switch is on)."
What is "I've"? amd which position is the ignition switch in when get "I've"?
Should be
I connected a wire to pin 81 and plugged the relay back in. remarkably I had 12v on the wire(only when the ignition switch is on). The position of the ignition switch is in the ON position when I get 12v to pin 81 and that's only when I connect a wire to pin 81 on the relay. I take the relay out and get nothing to socket connector 81. I'm considering running a wire from ignition sw start wire(yellow) straight to the starter relay pin 81 and bypass the bcm all together. Oh yes I thought the voltage was getting dropped in the bcm so I replaced it also before contacting you. Chances of 2 bcm modules being faulty is almost nil.
AnswerHi Don,
When you plug in the relay that results in pin 81 being connected to pin 83 albeit via the relay's actuation coil, and pin 83 is not only connected to the P/N safety switch (which would be either open or closed to ground in P or N) but also a wire from that pin goes to pin 76 of the PCM which is labeled P/N safety switch sense. That is the source of the 12v that you see on pin 81, so that is a plausible answer.
The yellow wire doesn't actually interact with the bcm, it simply goes to a disconnect, and comes out of the other side of the disconnect on a yellow/orange wire and then goes to the relay. Other wires at the disconnect are involved in the bcm, but not that one. The disconnect is not a plug of the bcm, just a nearby 'joint' (and is arrayed 2 x 8, black). It is the most obvious disconnect that you will see if you look under the dash at the lower front corner of the junction block/bcm module so it should be easy to find pin 8 of it where the yellow wire enters and yellow orange exits.
Don't blame the situation on the bcm! Check out the wire all the way to find where it is disconnected.
Thanks for the rating and the nomination; you can offer my up to 5 nomination (one per answer) if you choose.
Roland
Revision: When you saw 12v on 81 with the relay in its socket AND a wire plugged in to 81, and I explained that was coming from the PCM having 12v coming to pin 83 from the P/N sense function of the PCM, I assume that you had the trans selector in some position other than P or N, otherwise pin 83 should be grounded by the P/N switch. Do you recall whether that was the situation? If it showed 12v even when the trans was in P or N, then I would wonder if the P/N switch is indeed connected to pin 83. So in addition to figuring out the continuity issue with the yellow wire, if that was the situation on 83 then that P/N not grounding too will need to be addressed. So to check that, see what 83 shows with the relay removed and the key in the run position, and note whether it goes to ground in P and N, which it should.
