weird electrical problems

[lilskyline240]

Ive had these problems since i bought the car and i decided that maybe someone else can help me out1. Dash lights/HUD dont work unless its been hot inside my car, then they work fine until i turn the car off and it cools off inside2. Wiper Delay doesnt work3. When i put my windows up and down the rpms drop about 150rpm at idle4. Headlights go up with the switch, but wont go down5. when my HUD/dash lights star working, my idle raises 150rpm6. if i turn off the car with the sterio on and the left door open, the radio wont shut off unless the door is closed

Im hopeing most of this stuff is all one thing.....i thought it might be the TCU so i replaced it with a junkyard one, but idk if the one from the junkyard was good either. I know my original one was bad cuz i took it apart and found some burn marks on the circuit board

Ive checked all fuses and relays and nothing seems to be blown...

the car is a 89 coupe with a DOHC motor swap

[Un4Scene]

Sounds like a pretty strange set of problems to me. But first things first. Have the charging system checked. The alternator, battery, cables, etc... And make sure that when the battery is tested they check the amperage under load, not just the voltage. It wouldn't be a bad idea to have it tested twice either. I've seen alternators and starters test fine the first time, and fail the second time. If you have something pulling a large draw from the battery, like a big sounds system perhaps, then you may need a stronger alternator. I know this sounds like basic stuff that you wouldn't think would cause these kinds of problems, but I've seen some wacky things happen just because the battery or alternator was bad. Also, if you don't have a sealed battery make sure you check the fluid level in it. If it's low you can fill it with any de-ionized water. If you have any oxidation or corrosion on any of the terminals it would be wise to clean it up. Just scrub down to shiny raw metal with a wire brush or something to insure you are getting good contact. If all of this works out fine, then you've probably got some shorts in the wiring system somewhere. Some of the stuff you listed has nothing to do with the ECU, so if that was bad, it wasn't the only problem. You might wanna check the fuse and relay panels too. make sure there is nothing arcing between terminals, or grounding where it shouldn't be. check the relays and see if there are any common relays between the problems you are having. Beyond that, I'm noit sure what else to tell you, other than take it to an automotive wiring specialist. Good luck!

[TravisD]

I had all kinds of electrical problems before I replaced my fried HUD/Digital speedo (I took out the HUD and replaced the cluster with an analog one). All my dash lights would go out, my battery wouldn't charge, the locks were acting up, and I have the headlight problem too. I can't remember all the problems, but replacing the gauge cluster put an end to my electrical gremlins. A bad ground connection (there are a bunch) will cause craziness too. It really sounds like you just have the Nissan Digital Disease. Note: except my headlights. They still won't go down sometimes when I turn them off; those times I have to use the button. That might not be related, or is permanent damage. I don't know. I haven't gotten around to diagnosong the problem. The HUD/Digital speedo thing is normal. They aren't the best designed piece of work.

[lilskyline240]

well after researching heavily last nite, im goin to go and get a couple more TCU's this weekend and try them, along with some Dimmer switches out of a junker...if that doesnt work im goin to try to ground the Red/yellow wire by the sterio to a chassis ground..

if none of that works....im scapin the HUD and goni with analog

[TravisD]

Get an analogue cluster first. Then you can figure out if there are other problems. I promise you it's causing some/most of them.

[lilskyline240]

i need to try to find an analog cluster/harness first tho. Kinda hard to find one. all the junkyards i know dont have them because they have been riped out already