Putting together a car that hasn't run in 8 years or so. with the harness back together, everything "works": signals, hazards, brakes, headlights, radio, blower, etc.

I found out in another thread I have a problem with the headlight circuit, and I have the upgrade from MSA on order (3-5 weeks, time enough for me to possibly get engine going). I'm also going to order the alternator upgrade because I have the original 40A one, but that's kind of less urgent as car is not yet running.

Setting that aside, what I noticed: when the hazards are on, the glovebox light pulses in sync with the hazards, and the stereo turns it self off during the hazard cycle, then tries to restart in the trough, hazard hits peak, it stops again, etc. Also, with hazards off, but blower on, the radio looses too much power and shuts down.

Some things I've tried/experimented with:

1. 10 AWG dedicated line from stereo ground to bolt in engine bay (not negative terminal, just a bolt that would have held a hood bumper): stereo survives hazards. Does not survive blower.

2. Sanding down the main ground point on engine side wall near starter motor, including shining up the bolt: with stereo ground back in "normal" position connected to a bolt under the dash: same results. no benefit detected.

I could route a permanent ground wire for stereo through the firewall to the battery, but doesn't sound like it's going to solve problem of the blower.

Any advice?

Look for corrosion around your fuse box, especially underneath.

I'd measure battery voltage first. Not clear what you're starting with, maybe the battery has just run down. Also/or, is this with engine off or engine running?

Sounds like it’s just battery power at this point.

3 hours ago, SteveJ said:

Look for corrosion around your fuse box, especially underneath.

hmm.

2 hours ago, Zed Head said:

I'd measure battery voltage first. Not clear what you're starting with, maybe the battery has just run down. Also/or, is this with engine off or engine running?

The engine isn't running at this point. Trying to get electrics sorted first. I have battery on a maintainer. It measure 12.6V at the battery. I did this test yesterday, and this is from memory, but at the stereo, when using ground point near the stereo, it was getting something like 11.2V when hazards were in the "off" part of the cycle, and 9.8V maybe when hazards were in the hi power part of the cycle. Might have been 11.8 and 9.2. I didn't measure them with a dedicated ground for the stereo, just observed that stereo didn't shut itself down.

Probably obvious at this point, but this is an aftermarket head unit.

That fuse that suffered the meltdown is for the parking light circuit.

The fuse for the radio is on the top right. It's on the same circuit as the blower motor. Put a 10A battery tender on the car and run the test again.

For the melting down fuse, you may want to look into the Motorsport Auto fuse box replacement. It should be listed on this page, but it just keeps blanking out on me: https://www.thezstore.com/category/543/fuse-amp-relay-boxes

The wire sizing for the parking lot circuit was marginal at best for a 20A circuit. You can get that circuit down to about 1A by changing all of the gauge bulbs and exterior bulbs to LED.

Same here, Page comes up with no information.

https://www.thezstore.com/product/4749/msa-fuse-box-long-pigtail-70-71-240z

will do more testing tonight and report back.

That’s a great graphic of the fuse box, thanks.

I wasn’t planning on doing LEDs but I think I will if it will reduce load in fusebox and under dash wiring. That fuse box point is not the only heat problem I’ve seen in the wiring. I replaced the ammeter/alternator blade connectors already but…

If you've seen issues with the wiring around the ammeter, that could be contributing to the issue you are seeing. When the car isn't running, the power for all of the circuits except horn, brake lights, and hazard lights travels through the ammeter. If the connections at the ammeter are heating up (higher resistance), that can drop the voltage.

This link to MSA works for me:

https://www.thezstore.com/product/4749/msa-fuse-box-long-pigtail-70-71-240z

A couple of points on the MSA fuse block:

When I bought it 15 years ago, it came with butt terminals for the high-amp wires - not the OE spade terminals. Also, the dimensions are different and the OE cover will not fit. Other than that I am well pleased with the part, it is a great upgrade.