'85 Electrical Problems - HELP?
Thread Starter
Instructor
Joined: Oct 1999
Posts: 145
Likes: 0
From: San Francisco, CA, USA
'85 Electrical Problems - HELP?
I'm still having a very bizarre electrical problem with my 85. For no apparent reason, ALL electrical power will just disappear. This only happens after the car's been sitting never while it's running.
Sometimes I get in and the courtesy lights are on, everything looks fine. Then I put the key in and turn the switch and EVERYTHING goes out. No electrical power what-so-ever. Other times, there's no power right from when I open the door.
It's not the charging system, I'm not having any problems with the battery and I've checked all the grounds and power lines. Since there's no power at all, I think I can eliminate the switch. If it was the switch, there'd be un-switched power, right?
I'm totally at a loss and am hesitant to take this to the dealer since it's intermittent and they can never troubleshoot those types of things.
Is there anything on the car that would go on the blink that would cause this TOTAL loss of electrical power? I thought it might have something to do with the theft deterrent system, but I don't think that total switches off the electrical, just the starter circuit.
Any suggestions would be GREATLY appreciated. Thanks in advance.
Sometimes I get in and the courtesy lights are on, everything looks fine. Then I put the key in and turn the switch and EVERYTHING goes out. No electrical power what-so-ever. Other times, there's no power right from when I open the door.
It's not the charging system, I'm not having any problems with the battery and I've checked all the grounds and power lines. Since there's no power at all, I think I can eliminate the switch. If it was the switch, there'd be un-switched power, right?
I'm totally at a loss and am hesitant to take this to the dealer since it's intermittent and they can never troubleshoot those types of things.
Is there anything on the car that would go on the blink that would cause this TOTAL loss of electrical power? I thought it might have something to do with the theft deterrent system, but I don't think that total switches off the electrical, just the starter circuit.
Any suggestions would be GREATLY appreciated. Thanks in advance.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
If you lose your radio presets and the cluster resets mpg, miles to go, etc., then you are losing the power from the battery. When this happens measure the battery terminal voltage. Your symptoms are classic poor battery cable connections. Remove the battery cables (neg first) and clean the cable lugs, battery terminals, and bolts and replace the cables (neg last). With a good cable connection, if you still experience power failure, you may have a battery with a bad terminal or intercell connector. Also you might have an intermittent connection of the battery ground cable to the frame, it should be clean and tight too just like the battery connections. Further, you could have an intermittent connection between the battery cables (either one) and their lug that bolts onto the battery terminals. One thing you might try when you lose power is to turn on the headlights and then open the hood and wiggle the battery cables and see if the headlights operate in accordance to pushing or pulling on the battery cables. Good luck.
Thread Starter
Instructor
Joined: Oct 1999
Posts: 145
Likes: 0
From: San Francisco, CA, USA
Well, it appears that my problems is a faulty connection with the positive battery cable. When all electrical fails, if I pull on the cable, it comes back.
However, I'm having trouble finding the connection where this is occuring. Can anyone give me a hint where the first connection for the positive cable is? It appears to leave the battery and disappears at the back of the engine.
Any help is greatly appreciated. Thanks.
However, I'm having trouble finding the connection where this is occuring. Can anyone give me a hint where the first connection for the positive cable is? It appears to leave the battery and disappears at the back of the engine.
Any help is greatly appreciated. Thanks.
Advanced
Joined: Mar 2004
Posts: 98
Likes: 0
From: No. Cali ca
http://forums.corvetteforum.com/show...84&forum_id=48
i have pics of where the horn relay is. its number 2.
i have pics of where the horn relay is. its number 2.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
My 87 did the exact same thing mate, but i didnt lose radio presets or any fuel/trip info on the dash, however everything apears to be 100% dead. when it happend i could here a spark sound coming from under the hood somewhere. I never did track it down, it wasnt the battery or the cables from the battery on mine. It only happend a few times over a few months. Ive traded the car on a 94 now.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
There is a red wire that comes out of the positive cable lug on the battery that goes to the start junction block behind the battery (bolt with 8 wires under its nut) and this wire may have an intermittent connection to the lug. FIRST remove the battery cables (neg first) and clean the cable lugs, battery terminals and the bolts and replace the battery cables (neg last). The battery cables become corroded due to the sulphuric acid fumes that come off the battery and make poor electrical connections to the battery terminals. You want your battery connections to be like your lover, bright and tight! 
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Racer
Joined: Mar 2004
Posts: 252
Likes: 1
From: Troy Illinois
I had the same problem with my 1985. It was a poor connection at the + battery cable. I bought a new battery (threads were slightly stripped in the old battery - used the old battery for boat motor). I also bought new battery terminal bolts (threads on old ones were also slightly worn). I also bought a battery terminal wrench. Removed both cables and cleaned with baking soda and water. Installed new battery. Installed new bolts into cables. Tightened them using the battery terminal wrench. Everything has been fine since. I also check the battery terminal bolts are tight whenever I have the hood open. Good luck!
Race Director
Joined: Jul 2001
Posts: 14,604
Likes: 3
From: Glendale, AZ
same problem on my 85 too - got stuck in kingman on the way home to phoenix from vegas!
turns out that the cable had a kink in it or something - so i replaced it with a cable from napa (super long) and the best way to be able to fee the new cable is to tie a length of jet-line to the end you are NOT pulling from and it will feed the jet line through then tie the jetline to the new cable and pull it back through.
what's jet line you ask - that's the "string" stuff that cable installers use to fish down walls and such to be able to pull data and phone cables through!
turns out that the cable had a kink in it or something - so i replaced it with a cable from napa (super long) and the best way to be able to fee the new cable is to tie a length of jet-line to the end you are NOT pulling from and it will feed the jet line through then tie the jetline to the new cable and pull it back through.
what's jet line you ask - that's the "string" stuff that cable installers use to fish down walls and such to be able to pull data and phone cables through!