[JoelEspinoza]

I have an 89 CRX HF, mostly stock with pretty virgin wiring. A while back I had a phone charger short out internally and popped the fuse for the radio/lighter/clock. I replaced the fuse but nothing came back on. Started looking into it today and turns out the radio and lighter are both getting a bit over 3v, like maybe 3.15-3.3v. I checked at the fuse and it is getting the correct 12v.

If it was 0 voltage I would assume I had a burned wire or fusable link, if it was 12v I would be fine, but what the heck could be making it 3v? Any ideas?

 

[mattliston]

high resistance short.

id just rewire. does it change if you ground the black wire at socket versus through harness

 

[JoelEspinoza]

high resistance short.

id just rewire. does it change if you ground the black wire at socket versus through harness

Both the stereo power and lighter power were checked with the multimeter common leg against chassis ground, I can check vs the harness ground wire and get back to you.

I am not going to rule out a high resistance short, because I am not an electrical expert, but I have a super shitty battery and I think if I had that kind of short I would be seeing the battery dead more often.

 

[Paterico]

That’s a strange one. Sounds like some wiring may have gotten burned up but I would have expected the fuse to blow before the wire sheathing got hot enough to melt.

I would test resistance between the fuse and the cigarette lighter socket and trace as much of the wiring as possible.

 

[mattliston]

Shitty battery? well, an alternator working hard to make up for a poor condition battery can certainly cause some very strange issues.

Do you have any spare batteries to temporarily hook up while you test further?

Also, CRX/civics of that vintage suck donkey balls for ground wiring underhood.

Make sure these are good

-battery NEG to chassis
-trans to chassis
-valvecover to chassis
-harness ground wire to thermostat housing


Also, throw on a spare that bolts at distributor mounting, and goes directly to battery NEG if you can. That one is more for ignition performance than anything though.

 

[JoelEspinoza]

Resistance between the fuse and the stereo/clock lighter wire seemed pretty much infinite, so I assume the wire must have burned through or something. No clue how/why it was coming up with 3v.

I just connected the stereo unkeyed power to the fused wire coming directly from my battery to my amp, which is right behind my stereo, now everything is working again and I will track down the burned/disconnected wire problem later.

My car battery is pretty weak, and I drive a VERY short distance to work every day, so my battery tends to run down over time. As soon as I fixed the issue, which was on my lunch break, I plugged my solar trickle charger back in and by the time I went home about 3 hours later starter blazed to life like it was serious, I dont know if anyone else here has a solar charger on their dash, but damn they seem to work pretty good. I have this one: https://www.amazon.com/gp/product/B01MYVUSRH/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

 

[bobski]

There's a 4 pin relay hiding out on the back of the rear support bracket for the stereo. It's controlled by the ignition switch ACC contact (yel/red wire w/ 12V in ACC position, blk wire w/ ground) and the contacts link constant battery power (wht/blu wire, 12V) to the stereo and cigarette lighter ACC power wire (wht/grn, supposed to get 12V in ACC).
I would unplug that relay and check that you're getting proper power and ground to the connector pins, and ohm the wht/grn wire from the relay connector to the stereo and cigarette lighter connectors. If that all checks out, your relay died.