Problems: no power

[CCG789]

I was driving down the road and all of a sudden 87 GN just stalls out. I pull over to the side of the road and it wont start, nothing no clicking from the started nothing, it was dead. I tried playing with the key in the ignition and I got it to crank for a second then it stopped, and it was dead again. So I had a friend tow it home for me. I just assumed that it was the ignition switch, so I changed it. I hooked the battery back up and it started, it ran fine, then I put it into reverse and it stalled, and now nothing works, no cranking from the started, no courtesy lights, no horn, no hazard lights, no brake lights, no nothing, its like there is no battery in the car, the only thing that works are the headlights, the parking, and dash lights that come on when you turn on the head lights, that’s it.

Things I have looked at:

I check that battery with a voltmeter it reads about 12.77v, I also load tested it and it ran about 740 CCA.

At the alternator it ran about the same, but only if I used the battery as a ground, if I used the fender it was only .6-6v, which means I must have a grounding problem, but I cant find it. If I used the motor as a ground the readings were jumpy.

I have looked at several grounds and they all seem to be fine, I even cleaned a few of them.

Is it possible for the ground wire from the battery to go bad, if so why do the headlights still work and nothing else does.

Any help please

chris

 

[CCG789]

Dam Car

I got all the grounds on the car to work now. But I still have no power at the fuse box, I took the ignition switch off and checked the voltage at the terminals. There is a blue connecter and a black connectors for the ignition switch, the only terminal that had power are the one with the red wire, it read 2.5v. I know that’s not right so what could it be? The only thing that works are my head/parking lights and the dash lights that go with them everything else is dead.
chris

 

[Brian Mc]

Sounds like one or all of the fusible links at the starter. They are subject to a lot of heat and can break from age.

 

[trading t/a]

Definately a fuseable link. Take an ohm meter on each side of the link and see if you pick up resistance. On most meters there is a buzzer that sounds when the circuit is completed. If you push the tip into either side and dont get a ring or beep then the link is blown....

 

[CCG789]

How would I go about replacing a fusible link? Would I just cut them out and splice in some new ones?

chris

 

[trading t/a]

YES. A partial harness from the dealer is available to splice in. Had to do that to my t/a when the header melted them.......

 

[CCG789]

Do you still have the part number? Ill go out tomorrow and test the links resistance. Are the fusible links the little black boxes on the wires? Thanks for your help ill let you know what I find.

 

[trading t/a]

I don't have the part #, but yes they are what you think they are. Just go tp the dealer and tell them you need a fusable link partial harness. A good friend of mine got my repair harness through the regualr part ordering center. If you have a problem you can always go to the j-yard and cut out what you need, they are pretty much the same for all cars in the 80's.......

 

[SpeednV6]

Wow, talk about coincidance! The same exact thing happened to me last night. The car was fine when I shut it off. When I went to start the car, could not. Changed batteries, it started. Drove it a mile and the scanmaster was spitting out codes and the cars instruments were going haywire. The car then died and could not be started. No lights, no hazards, no power at all. It drained the power out of the replaced battery. I did check the starter, and it did have some loose wires. My harness is brand new. Do I need to change the starter or the wires?

 

[trading t/a]

Just the wires that come off the starter that have the two little black covers on them(they are the links).

 

[CCG789]

All of the fusible links are fine, but I did find something, it looks like someone bypassed one of the links with a regular wire, the insulation on the wire was brittle and parts of the wire were exposed, the connector that was used looked like it got hot! it was brown and burnt. IM not sure what the wire goes to I think it is for the cooling fan. Next thing I looked at was my cooling fan relays (the three on the drivers side). The connector on the lo speed and the connector on the delay relay are all melted I don’t think I can even salvage them, the middle relay looks fine.
I connected that one wire to the battery to see where my power went, I could find it. I ran an ohm test on the wires running from the starter to the ignition system and I got continuity, but the ohm reading was almost 4 to 6 ohms. When I reconnected the battery I was getting about 6 volts to the red wire at the ignition switch connecters.

IM going to replace the frayed wire with a fusible like from the parts store. I still haven’t been able to get power to the fuse box.

Where should I go from here? What should I do about the melted connectors on the fan relays? thanks.
chris

 

[trading t/a]

then you have a problem. You should get the same voltage at the starter as you do on the battery terminal. Somewhere a power wire is going to ground. I wouldn't worry bout the fan relays yet. You might have to seperate the loom and find out why you are not getting power to the fuse box first.

Did you check the firewall connection? If you have power there then the first place to look would be the fuse box. Check to make sure you have 12.9 volts at the battery terminal, with it going to ground(as it seems) it might have drained the battery. After you check these areas the only other thing to do is to open the harness and look for bare wires either touching each other or grounding out on the chassis or engine. Hope this helps...................

 

[CCG789]

Thanks trading t/a every bit of input helps when trying to find a electrical problem.

That connecter at the firewall is called C100 in the shop manual. That is the next thing I am going to check out. Ill bet that the connector is melted just like the fan relays. Well, ill find out tomorrow, I have all day to work on it, no work. If I don’t find the problem tomorrow ill just set the car on fire in my driveway, maybe not.

chris

 

[SpeednV6]

Well guys...thanks for the input.

I found my problem. My positive wire from the battery was melted onto my header. My battery also contained a dead cell.

Thanks----Pete.

 

[CCG789]

Now What?

Well I found the problem. I took a look at connector C100 which is the connector on the firewall that connects everything to the passenger compartment. Both sides of the connector are completely melted.

From what it looks like there is a small rusty hole in the firewall just above the connector, and it looks like water got into the hole ran down the firewall and into the connector. The connector is NOT a weather proof connector, when I went to unscrew the bolt that holds the connector together it was not very tight, and the seal at the end of the screw was all messed up. I put some RTV on the hole to seal it.

What should I now? I’ll call Caspers and see what they have to offer. Should I replace the whole engine harness or just the connectors? That is a lot of splicing. This connector has like 45 cavities on it, IM no electrician; I hope I don’t get anything wrong.
chris

 

[CCG789]

Just the plastic around the connector is all melted, the prongs are all fine. The female side of the connector is a mess, all the plastic is melted. What could I use to clean the melted plastic off the prongs? It’s a scammer mess!

I see that Casper sells the C100 connector, im not sure how it comes but is 30 bucks, ill call Casper on Monday to see what they have available. What a mess this is!

chris

 

[CCG789]

Nice to have power again

I got the GN all powered up again. I got the C100 from Caspers, John was a great help. I still need to replace the connector that is behind the fuse box, it has a burn hole threw it the size of a pencil.

Until I get that connector I ran a wire threw the hole and connected it myself, then I slide the assembly together.

My question is if all the G-bodies have the same connector that goes threw the firewall? I know the wiring is different but I just need the plastic connector behind the fuse box. I’ll just take the terminals out of my old connector.

chris

 

[Chuck Leeper]

Melted?

The "gooey stuff" in the connector is most likey not melted plastic.Itsa sealer that is put in the plug cavity when the car was assembled. If it was melted plastic, when it cooled, it would likey return to a hardened state...

 

[CCG789]

Ya that gooey stuff is the sealer that GM used back in 87. But there is a pencil size hole threw the connector behind the fuse box, the one that goes into the firewall. Luckily none of the cavities around the red wire are used so it just melted the plastic.

The hole is were the red wire got hot and melted the connector. The red wire is the one that goes to the ignition switch (the black connector, not the blue on the ignition switch).

I need to know if all the G-bodies have that same connector that goes threw the firewall? Or if the GNs had there own unique connector?

chris