Running lights don't work/blown fuse

[kmack]

Ok, I'm kind of stumped on this one.

After coming back from racing the Z this past weekend, I've acquired a problem. The running lights, dash lights, and tail lights are no longer working in my car. Headlights and brake lights all work.

They were working when I unloaded the car off the trailer Sunday night after getting home. I know because I had to turn the lights on to see what I was doing. Drove the car to work on Tuesday, it ran fine all during the day, but of course the sun was out and no need for lights. Got in it that evening to run to the store and the lights didn't work. Fuse was blown, so I put another in. Popped it within a few minutes (less than 10 minutes). They worked fine with the new fuse, but as I was checking a few other things, the fuse popped again.

Messed with it again on Wednesday night. I looked for any loose wires under the dash and could fine none. Put a new fuse in and the lights worked great. I left them on for almost 30 minutes with no problems. I closed up the garage satisfied it was a simple fix. I grabbed a couple of extra fuses to put in the car but got them mixed up with the fuse I had just pulled. The fuses all looked ok so I put a continuity test on them. Every one of the fuses were good! What!?! I was happy the lights were working again, though.

Last night I checked them again because I wanted to drive the car today. No workey! I didn't have time last night (Halloween decorations) to get more involved with it, but this one is confusing me. Is any of this making sense? Anybody have a similar problem? I know I should be looking for a grounding problem or some loose wire, but this is starting to seem a little more complicated. Or is it? I don't know anymore....

[bryantatem]

Why don't you ask Troy?? He is an expert about this same subject...

I'd bet my last $2.00 that he is STILL having the same problem...

[Dtsnlvrs]

sounds like you got a short in the combo switch

[kmack]

Do you think it could really be in the switch?

[civ104]

Ken,

I went through this recently and found a couple of things. First my right front running light socket was seriously corroded, but the kicker turned out to be that an overlong screw was holding on the left rear light and was shorting the hot line to ground. Put in a new fuse and turn on the lights, fuse isn't new anymore. Took a lot of troublshooting to find that one. Probably had been there a long time. One question, do you have your instrument lights?

[kmack]

No instrument lights. They go out with the running lights.

Btw, I have checked the condition of the fuse holders. They are clean. I went through this before once and rebuilt the fuse block. So I'm left to believe the problem lies somewhere other than the fuse block.

Thanks for the replies, keep them coming. I need all the ideas I can't think of!

[Dtsnlvrs]

All the power for the light travels thru the hazard switch and the headlight switch. If you have no dash lights, side marker lights, or parking lights I am inclined to say that it is the headlight switch....if it was the hazard switch you would still have the side marker lights and dash lights. It is the only thing it could be other than some strange short.....besides should you not replace that 30 year old switch anyway. If the problem re-appears you will have a nice new switch to operate the functioning system once you find the short that iI seriously doubt you have......BTW if you order a new headlight/combo switch make sure and order a new turn signal switch as well. It is one of those "while I am at it" parts.

Good Luck,

[Zedrally]

Before you go to the expense of buting a new switch, try cleaning the contacts with a contact cleaner, you could even give it a squirt of CRC etc.

If there has been any buildup there this will loosen it and re-jevinate your switch at the same time.

[Rusty1]

check some of the recent threads where guys have listed prices for replacement switches, switch blocks are bulk expensive...

If you ever needed motivation to try to fix a switch yourself there is is, you never know, you might even succeed...:classic:

[Dtsnlvrs]

I have fixed many a fuse block and hazard switch on a z-car (both are nla for 240's) but i believe that if the factory replacement switch is still available it should be used. The original switches lasted over 20 years on these cars, and a new replacement switch will last longer than we will be able to keep most of these cars on the road. 100 bucks or so for a new headlight combo switch is pennies if you consider the cost of a wiring harness meltdown if a repair is faulty. Just my opinion here.

[SledZ]

I'll bet one of the wires that is plugged into your running lights are backwards. The PO of my car did and I just figured it out. They ran fine for a year and then started blowing, traced everthing and found out it was the right rear running light wires were reversed. They can run that way because they can be insulated from the rubber gaskets, but once they shift enough and the casing touchs the screw,, pop! I was relieved

Also the parking light switch is just that a switch. you can take off the molex connector and short the green/blue - green/white wires and make sure it isnt your switch.

[Murph]

I've had this same problem before, but as everyone else said, it could be many many different things.

In my case the solder join between the running lights wire and the switch itself had heated/melted/moved over time till the solder was touching the switch's metal casing, shorting it out. I desoldered the join, then resoldered it properly.

The whole problem was that it was dodgily soldered by the previous owner (they'd completely mutilated the wiring in this car ). The solder joint only had a small contact area, so heated up, melting the solder thus allowing the wire to move and short out on the casing.

I'd recomend you get in there with a multimeter and start debugging it. Work your way up from the fuse box. Good luck.