Electrical problem

[Esteban]

The runnning light work fine. But when i turn on the headlights the running light go out in the front. Is this a switch problem or a wiring problem?

[wayno]

Likely the fuse block, I would look there first.

I had an issue that whenever I hit the brights, I would lose my headlights, when I wiggled the fuse block wires in the rear, headlights would come back, but I would lose the running lights, it was a fight trying to get the headlights and running lights working at the same time, the worst part was I was within 20 miles of getting home from a 2500 mile trip, and I had been driving 16 hours straight that night.

A fuse block fixed most the issues, now it is the power to the turn signals, gauge power, and alternator light acts up even though it is charging.

[DanielC]

By running lights, do you mean the amber park/turn signal lights?

 

Here is a diagram of the light circuits on a 521.

This is the whole electrical system

 

On a stock 521, the headlights have a dedicated ground wire, that is on a lug, grounded by a bolt that holds the voltage regulator to the inner fender.  There is also a second ground wire that goes back to the alternator frame.  The park and turn signal lights are grounded  to the cab sheet metal.

 

Never trust a fuse that looks good.  They can fail internally, and still look good.  Check for voltage on the park light fuse, with the headlights on, and off.  Check the side of the fuse away from the battery.

[Esteban]

I found the problem. It was the switch. I found a spare. Thanks for the tips.

[banzai510(hainz)]

Mike Klotz has a write up on cleaning up those switches. There really simple and ez to keep working.

bet the sliding copper strip just wore out in a spot

[4perrev]

Install a new fuse box and it will sole many of those old electrical problems. I got this out of an old altima from the junkyard. Glad it was just a switch though!

 

[Esteban]

Ya i was thinkin about putting a new fuse box in. I'm sure it would help in the future. Thank for the tip on the altima fuse box.

[4perrev]

This box was the one under the hood, not the inside car one. Just made it easier to get out. Had to do some creative wiring, because 2 of the 6 fuses were bridged, while the other 4 of 6 were bridged as well. So, I had to run 2 sets of wires from the engine bay into the cab for the fusebox. Took a bit to figure out, but not very hard.

[datzenmike]

Some fuses are powered directly from the battery, like horn, headlights, brake lights, dome light, clock. The can be used at all times. The others are turned on by the ignition switch like wipers, radio, heater fan...