Electrical issue - no start
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
I have infinite resistance on both battery cables. Removed the negative cable from the bottom side of the engine and the ground from underneath the battery, both connections were good but I cleaned them anyway. I still have no power.
Where is the reverse lockout relay and how do I test it?
Where is the reverse lockout relay and how do I test it?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
When your car quit running, did it just die while you were driving ?
(if this is the case, then the ignition/NS switch/SIR etc. is not problem)
Or did the car just not start after you turned it off at some point ?
(if this is the case, then the ignition/NS switch/SIR etc. could be problem)
Team Owner
Joined: Jan 2003
Posts: 20,297
Likes: 240
From: Summerland B.C. Canada
Sounds like you need to test fusible link "A" and then check to see if power from "A" is making it to the fuses and ignition switch and fuses powered by ignition switch.(based on my 86 info)
http://members.shaw.ca/agent86/Power%20Distribution.pdf
http://members.shaw.ca/agent86/Power%20Distribution.pdf
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
It died while I was driving and didnt show any signs that it might die beforehand.
Agent, my wiring looks a little different I think. If I were to follow the wiring out of the junction block coming out of the firewall, the first two fuses are right next to each other, both have 12 volts going through them. I assume these are M and A? After that the next one comes off the positive battery cable and goes into the junction block wiring. There is one more immediately after that.
The diagram you have doesnt look anything like mine. I just have the huge bundle of wires coming out of the firewall behind the battery. In your diagram it looks like a junction block below the battery or something.
So if I have power going into the firewall, but none going into the neutral safety switch wouldnt that mean it has to be the ignition switch?
Agent, my wiring looks a little different I think. If I were to follow the wiring out of the junction block coming out of the firewall, the first two fuses are right next to each other, both have 12 volts going through them. I assume these are M and A? After that the next one comes off the positive battery cable and goes into the junction block wiring. There is one more immediately after that.
The diagram you have doesnt look anything like mine. I just have the huge bundle of wires coming out of the firewall behind the battery. In your diagram it looks like a junction block below the battery or something.
So if I have power going into the firewall, but none going into the neutral safety switch wouldnt that mean it has to be the ignition switch?
Team Owner
Joined: Jan 2003
Posts: 20,297
Likes: 240
From: Summerland B.C. Canada
I was hoping that the wiring would be the same with the exception of the MAF relays.
The ignition powered fuses should be the same so you should be able to test for 12 volts at those fuses, with ignition on.
Your car died while in motion, so I wouldn't spend any time chasing power to the starter interrupt switch.
You need to find out what wire going in and out of ignition switch, is responsible for powering the fuses required to make the engine start and run.
I'll dig into it some more.
The ignition powered fuses should be the same so you should be able to test for 12 volts at those fuses, with ignition on.
Your car died while in motion, so I wouldn't spend any time chasing power to the starter interrupt switch.
You need to find out what wire going in and out of ignition switch, is responsible for powering the fuses required to make the engine start and run.
I'll dig into it some more.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
I've looked through every wiring diagram I can find and i'm having no luck locating fusible link A unless '84 and '85 didnt have it. I only have half of the FSM since there is no electrical section with mine. I sure do appreciate the help.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
I've got an '85 FSM right here what are you lookin' for right now?
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Team Owner
Joined: Jan 2003
Posts: 20,297
Likes: 240
From: Summerland B.C. Canada
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
There are 5 other fusible links that I know of on the drivers side near the battery.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
the book shows this also. There are quite a few fusible links for the system not all are by the battery on an '85. Let me know what diagram/system you are interested in and look it up and post it when I get back to the house later on today. The complete '85 books are very hard to come by these days....i only have one...if I had more than one I'd sell you one. Can you give me your no start issue and where you are in troubleshooting it in a nut shell.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
Thanks engle1147. The car just died while driving and after coming to a stop, I had no power to the dash and it wouldnt turn over. The headlights, interior lights, and key chime all still work though. Using a meter I have found that there is power at the starter. The fusible links near the starter are good and have power as well. I followed the starter circuit from there to the neutral safety switch. There are two wires on this switch, a yellow one and a green one, neither have power. The ignition switch would be the next item along this path and its supposed to be hot at all times. Even when turning the key there is no power to the neutral switch.
I determined that either the ignition switch is bad or there is a broken fusible link that feeds it. I tested the fusible links going into the firewall by the battery and they have power. The grounds for the battery cables are good too.
I determined that either the ignition switch is bad or there is a broken fusible link that feeds it. I tested the fusible links going into the firewall by the battery and they have power. The grounds for the battery cables are good too.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Thanks engle1147. The car just died while driving and after coming to a stop, I had no power to the dash and it wouldnt turn over. The headlights, interior lights, and key chime all still work though. Using a meter I have found that there is power at the starter. The fusible links near the starter are good and have power as well. I followed the starter circuit from there to the neutral safety switch. There are two wires on this switch, a yellow one and a green one, neither have power. The ignition switch would be the next item along this path and its supposed to be hot at all times. Even when turning the key there is no power to the neutral switch.
I determined that either the ignition switch is bad or there is a broken fusible link that feeds it. I tested the fusible links going into the firewall by the battery and they have power. The grounds for the battery cables are good too.
I determined that either the ignition switch is bad or there is a broken fusible link that feeds it. I tested the fusible links going into the firewall by the battery and they have power. The grounds for the battery cables are good too.
Last edited by engle1147; Jan 5, 2009 at 01:50 AM. Reason: error..error...error...all better now.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Ok so the questions I asked will make a little more sense if you look at the diagram.......and you may see where I was headed.....the questions would narrow the problem down to before, at or after the ignition switch with some quick checks. The horn question was asked because there is no Theft Deterent System fuse in the fuse box.....TDS is feed and fused from the horn circuit....TDS also closes the ground circuit for the start enable relay's coil which also is in series with the "green" wire side of the P/N switch. I can't get a better scan since this book is rivited together sorry....on a side note it took me a little longer to post this info since one of the neighbors called animal control to come out and wrangle an alligator from their yard.....normally this would be cool to watch but it was actually very cool since the wrangler was a woman.
We only get Polar bears
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
This may sound kinda bumb, but it will help me divide and conquer, Does the horn work? How about the door lock switches do they work? When you turn the ignition key to "run" does the "check" engine light come on? For the P/N safety switch you should be able to read +12v on the yellow wire with the key in the "start" position and the selector in park or neutral. Let me see if I can find my scanner......
Nice pet btw.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Thanks for the diagrams, this will help a lot. I dont know if the horn works, havent tried it. I definitely know that the door locks do not work. There is no voltage on the yellow wire in any key position while in neutral or park. I'll check the horn tomorrow.
Nice pet btw.
Nice pet btw.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
I tried the horns with and without the ignition turned on and its a no go. The battery is still very healthy so thats not the problem. Its something between Fusible Link A and the the fuse box along C100. It makes sense that my interior lights work because they're powered through Fusible Link B, i'm think i'm starting to understand this stuff better. Now i'm off to find some bad wiring.