Jump to content


Two overheated connectors above passenger's right knee (in U.S.)

Mikes Z car

Recommended Posts

I noticed these two overheated connectors to the right of the glove box (above passenger's right knee in the U.S.) on my 240z when I got it:


To fix them I soldered the four crimped connections between the wires and the two connectors to eliminate further overheating. I also slightly squeezed the gripping side edges of the two female connectors to grip harder on the connection and sprayed the connectors with deoxit, following up with dielectric grease. I understand that one of these two white wires goes to the battery and the other one goes to the alternator and between them they carry all of the current that goes through the fuse box. I have three questions:

1. Are there other ways to fix these two overheating wires such as bypassing the connectors by soldering (or crimping) the wires together to get rid of the two connectors entirely?

2. Is there any impact from having these connections overheat such as does increased resistance and voltage drop affect battery state of charge? Could impact take the form of dim lights or fluctuating gauges?

3. Or is the battery voltage sensed at the battery by a separate wire so the voltage regulator accurately sees the battery voltage allowing the alternator to accurately charge?

I notice my parts car shows overheating at these same two connectors.

Thanks for any ideas.


Link to comment
Share on other sites

I'm not sure that you can characterize this as an inherit problem with the early Z's . Maybe both cars had the same issue causing this. If the ends are badly damaged or not staying connected securely I would definetly consider installing new ends . Any looseness would cause this hot spot.

Could have been fusible links that didn't give out quickly enough and let the wires get hot? Either way, that's pretty hot to allow them 12 gauge wires to melt the plastic

Link to comment
Share on other sites

I believe the early car wiring harnesses got reworked some in the later cars. The later harness is a little different and the 73 harness is even different again. I don't know if the white wires were changed in any of the later editions. I have seen these white wires show signs of overheating on several of my cars...


Link to comment
Share on other sites

This type of problem is common to any old car, not just the Z. Fuses and fusible links not doing thier job is not the problem. The problem is caused by corrosion which creates resistance. Resistance creates heat which increases the rate of corrosion. After a while there is enough heat to affect the temper of the metal and the spring pressure is reduced and the resistance increases even more. After a while the insulation starts to discolor, decay, and eventualy melt. This happens slowly over a long time.

The solution is replacing the connectors with new ones. The large white and white/red wires are in the charging circuit, comming from the altenator, going to and from the ammeter circuit, and feeding the car. Therefor, they must carry large currents so make sure to use connectors rated for at least 60 amps. You will notice the original connectors are larger than the other connectoes in the car and larger than the standard 1/4" wide connectors commly available at the part stores.

Link to comment
Share on other sites

Mike, this might be overkill but I use this stuff all the time and love it,

Ox-Gard Anti Oxidant Compound - OX-100B Consumer Reviews | Epinions.com

Unlike dielectic grease, this stuff is conductive effectively giving you more surface area contact and a cooler connection.

And of course it helps prevent oxidation forming again.

Good for any single wire crimping, spade or bullet terminals, grounding points etc. NOT good for multi pin connectors!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.