The third brake light looks to be after market. My father in laws father, was a mechanic, this was his car originally, he may have added the light. Tomorrow I will post a pic of the dash box for that third brake light.
This box is likely for controlling electric brakes on a trailer.
canoe, harness pic. new stero to old stereo which would then plug into harness from car.
That's what I'm looking for, but in high res so I can check for the faults I suspect.
How are those wires joined under that electrical tape?
... I wonder if adding a ground specific to the radio would help? Someone with better electric experience might have a idea on this one.
The old radio worked. So its ground was good. The new radio worked. So its ground was good.
When the rear electric defroster was turned on, it somehow put high current onto the ground within that modified harness.
Apart from finding and fixing that connection, it's not a good idea to be providing alternate paths for current to flow, as that can have unintended consequences.
Sometimes one can identify a better way to do things, like using headlight relays to avoid bringing that higher current across the firewall and running through switches. But that has to be done right.
This car has had portions of its electrical system changed. Prior to the recent modification of the stereo connection, as far as is known, there were no faults noticed. That's a task to figure out with the various mods what was intended vs. what was done, and if that has caused or taken any damage. I would put that on hold right now.
Don't change anything, or you're making a moving target. Or worse, things start working, and you think you've fix the problem, but you've just provided an alternate current path and left the original fault undetected lurking to cause further, possibly worse, damage down the road.
The original incident involved the new stereo, the modified stereo connections and turning the rear defroster on. Those need to be thoroughly checked. Like checking the wiring connections to the rear defroster - were they changed from stock. What are they now (where does it ground). The ground wire for the stereo has to be checked back to its grounding and repaired as necessary.
Before the battery is connected, the ground to the car's body under the hood should be disconnected, cleaned and re-established to remove this
common fault point from the situation.
Do not skip this if the connection looks good; a number of cars that appeared to have a good ground connection had hidden corrosion (use dielectric grease to reduce this risk), that once cleaned and reconnected, returned the car to operating normally. If that cable/wire/strap's wires are corroded badly, that should be replaced as it may not be able to properly handle the required current or may be degraded enough that it's acting as a resistor. A replacement should be a sealed cable, like battery ground cables, so the wires are protected from corrosion.
Topic: electrical help needed (Read 16194 times)