Ok vehicle is a 90 civic si hatchback d16y8 5sp that suddently developed a problem. We drove it just a few yards from the house and after turning on headlights to high beam it died, fails to restart. Battery voltage is good, not even trying to turn over.

Now the weird part..with the key out the turn signal indicator lights and few other lights in gauge cluster illuminate themselves unless you disconnect the battery.

The battery measures over 12v, as do the fuses in the underhood fusebox, but at the ignition switch and at the in car fusebox there is only 5 volts? Wiring and connections look ok, and ive disconnected several things to make sure they are not creating a short, but the cluster lights stay iluminated like i said, regardless of pulling each of the fuses, disconnecting alternator, ecu, distributor from the harness.

What would cause only 5 volts at the interior fuse box and ignition switch that is causing my no start? Possible shorted fusebox or maybe something grounding out in headlight circuit? No blown fuses, all grounds look good. Anyone had this problem? Wish I had a FSM for EFs, need to get one have 4 just no EF FSM

 

check all grounds for good connections etc. something is shorting out and or not grounding properly

 

took the ICU off that plugs into back of fusebox, opened up to find a burn mark under the Q4 transistor. I went to the junkyard and got another ICU, opened it up and looked good. Got home, plugged in ICU and car started, and runs great, all the lights etc work properly. Drove it around several miles all day, still did just fine until I took it for another drive later on in the evening and it died on interstate, same issues with the lights staying lit in cluster and when it trys to turn over it seems to short. I unplug the main relay (its new, and ive tried 3 other good ones) and then it turns over without shorting out but obviously doesnt start (no fuel), but the turn signal indicator lights are staying lit still. I am guessing there is something on the lighting circuit that shares a same wire that comes out of main relay that is shorting to ground...now to find on this mess of a car....anybody had this issue?

 

Ok I finally got it to experience the issues by moving around gauge cluster or tapping it...yay finally found a location. I played with all the wiring going into gauge cluster and it didnt cause the issue, checked the ground etc, so figured it was just the gauge cluster itself. I took the cluster apart to find a nice suprise..a leaky capacitor that was shorted out completely feeding voltage into the ground circuit in the gauge cluster. The capacitor was a 2200uf 16v on the tachometer circuit board. I cleaned up the board and replaced the capacitor now all is well no more problems...lets give it a day or so before calling it fixed

 

good deal man. nice detective work