Electrical mayhem

[2000ElectricGreen]

I'll write this out as properly as I can, I'm suffering some electrical issues on a car I'm trying to "rescue".
2000 3.8L V6 Base Model, 180,000 km.

I've already fixed the misfires it had and got the engine running quite nicely, no CEL or anything.

Complaint:

1. Windshield wipers (VERY SELDOMLY) activate without user input / touching the multi-function switch.
2. Water leaks into the passenger side floor, front, and back. Drivers side remains dry.
3. Water leaks into the trunk. (found the leaks, figured this out, but it's relevant to my issue)
4. No tail lights, instrument cluster lights, headlights, signals, etc.
5. Gas tank pressure is not being relieved, unable to be easily filled due to triggering the anti-overfill.

Intervention / Solutions:

1. Trunk wiring harness shorted to ground, wires rubbed on the metal of the trunk, melted all wires from the first/rear-most connector to the license plate lamps.
   1. Cut all connectors, remade a harness myself, seems to work perfect. Not sure if this could cause the tail lights to not signal on, seems unlikely upon discovery of corroded headlight switch.
      1. This did not fix the evap / gas tank issue.
      2. Headlights, signal lights, brake lights, all function now, However,
      3. Tail lights and dash lights do not come on when turning on the headlights
      4. Found corrosion leading from the B1 Pin on the headlight switch (Battery Power to Main Light) down into the switch.
2. Silicone and JB weld for leaks in the trunk-- however, unable to find the leak in the passenger side dash area-- or wherever it's leaking into the carpet. Passenger seats, both rear and front, remain dry (I think that might mean it's not moving down the trunk into the passenger side interior?)
3. Found stereo wiring under spare wheel, in wheel well, bathing in water. Cut ends, insulated, however hasn't seemed to contribute to any issues besides maybe a parasitic draw.

If anyone has any tips or clues, PLEEEEEEEEEEEEASE let me know. I understand this is a cheap car and that it's not really "worth fixing" However it has great sentiment to me, and the experience of fixing it is well worth the time and cost, so junking / giving up is not an option for me.

What are the odds my GEM is malfunctioning? Just ordered a headlight switch, will update.
Took it out and inspected it, found corrosion from the main power pin leading down inside the switch, and around the axle which the dimmer knob rotates.

 

[squeak93]

#1 sounds like a malfunctioning multifunction switch.
#2 Check heater core drain on firewall - pass side below heater core. If clogged you will get water in floor. -sometimes will still get water in floor - these cars are getting older
#3 sounds like you have that under control
#4 Check fuses, grounds etc. All those are somewhat related. Do you have brake lights or is it all dead? - edit read your notes (You should keep numbering the same its confusing lol). What did you do about corrosion?
#5 Evap cannister unless I'm not understanding what you're trying to relay here.

 

[2000ElectricGreen]

#1 sounds like a malfunctioning multifunction switch.
#2 Check heater core drain on firewall - pass side below heater core. If clogged you will get water in floor. -sometimes will still get water in floor - these cars are getting older
#3 sounds like you have that under control
#4 Check fuses, grounds etc. All those are somewhat related. Do you have brake lights or is it all dead? - edit read your notes (You should keep numbering the same its confusing lol). What did you do about corrosion?
#5 Evap cannister unless I'm not understanding what you're trying to relay here.

My apologies, I was rather stumped and irritated when I wrote this, as I had just spent a dozen hours working on it to no victory.

In order:

#1: noted, will try to test and confirm. Never had issues with one of these so I was worried it was a bad relay or gem

2:
I haven’t seen any water draining from the heater core, and seeing as you brought it up, I fiddled a zip tie in the drain and then blasted a very light amount of compressed air into it. However, no water came out. It’s going to rain this week so we will find out in a day or two if that fixed it.


4:
I checked all my fuses and they’re all good, all have continuity. I rewired that trunk harness and now it is as follows:
Brake lights work
Signal lights work
Reverse lights work

- tail lights do not come on when headlights on, however brake signal reverse still work.

So I replaced the head light switch, corrosion seemed bad and I don’t think these are easy enough to repair to justify the 25$ cost.

headlight switch changed nothing,

I still lack instrument cluster lights and tail lights when headlights on,
When headlight switch is set to marker lamps/2nd notch (inbetween off and on), nothing happens with my lights.

I pulled the cluster, looked for issues- and couldn’t spot any.
I’m really frickin lost here. I must have an open circuit or something????
About to google if license plate lamps are parallel or daisy chained, as I just found the socket is corroded.

5: going to just back burner this one. Fixing the trunk harness relieved the issue slightly, as I suspect the purge valve wasn’t getting power and was stuck shut. Still happens, but at this point it’s the least of my worries.


I appreciate your help, I will update after testing multifunction and weather testing heater core drain!