Tach Reads 6500 With Engine Off, Lights On

[CarRacer]

Experienced a electrical problem on my car tonight.

I was charging a dead battery and turned on the lights. The tach jumped to ~6500 RPM and the dash made a rapid clicking when the lights were on. It didn't sound like a relay clicking, it sounded a little different, but I could be wrong.

A few wires on the harness near the ECU had been "repaired" by the PO. He twisted the wires together and put electrical tape over his epiq connection. There were 4 wires fixed in this manner. I previously traced these with the pinout. I don't remember these offhand, but I remember the tach signal being one wire that was fixed.

I used butt connectors and it didn't change the problem. While I installed the butt connector, I turned on the lights with the wire disconnected. The tach remained at zero. I didn't cross any wires, all colors matched up. ECU was disconnected during this time.

Any ideas? I fail at electrical troubleshooting. Thanks.

 

[CP]

I'm no electrical expert either, but I'd suggest you solder any broken wires going to the ECU and cover them with shrink tubing. The charger wasn't connected to the battery when this happened, right? Maybe unplugging the ECU for a while to "reset" it might solve this /ubbthreads/images/graemlins/dunno.gif

 

[BoostedAWD91]

u might have fried something, try taking the cluster out and looking at the back of it and see if anything looks fried. i dont remember if it is for the speed-o-meter or the tach but there is a components in the back of the gauge cluster that spins to read the speed. I dont remember exactly what it is called off the top of my head either. I would fix all ur ECU connections to make sure they are solid, and check out the back of the cluster and go from there

 

it could be a short some thing could be using its ground maybe a light thet is why it gose on when you tuun on the lights