On my 97, when I turn on the headlights, the tail lights go off. But when I just have the parking lights on, they are on. I checked the fuse panel and all is well. Could this be a grounding issue or maybe a fault in the switch itself? Thanks in advance...

 

Replace the bulbs and see what happens.
Even though they appear good they may not be.

Do your dash lights also go out?

 

well the bulbs are good and the dash lights do go out when I turn on the head lights. When the switch is in the first position, parking lights, everything works fine. I was reading some other posts about this issue and I used my tester to test power at the back of the switch. Good power at the red wire (parking lights) and good power at the head lights (blue and blue/red). I looked at the grounds on the side panel by the driver's foot area and all is good and clean there. I'm kinda at a loss here. Any more suggestions? Thanks for the help. It will be nice when I can drive her at night!!!

 

Look up RoverChris, he is a 12v tech.

 

Did you test tailight circuit at the switch?

I've gotten pretty good at pulling the switch, cleaning, building up worn contacts w/90/10 solder, etc.

It's in the rave cd, and is quite easy, (pay att'n to parts if you take it apart.)
do it over a nice clean surface.

luck,greg

 

Ok I think I'm getting somewhere now. I've narrowed it down to the switch. I've noticed that if I try to turn the switch a little passed the second click (headlights), the tail lights and dash come on. But any bumping will make them go back off. So I took the switch out and it looks very clean. Is it worthwhile to take it apart and try cleaning the internals of it? Or should I just say screw it and find a new(er) one?

 

I would just replace it, why go through all the trouble of removing it just to put it back and have it still not work?

 

It will look clean outside, the grease from the factory inside degrades to gum, causing poor contact - It screws together, making it serviceable.

I just cleaned mine inside with wd40 and a Q-tip.

If you go that route, do it slowly over a clean surface.

It's not a bad idea to take pictures during disassembly if you like.

Mine was so worn out that I built up the contacts with 90/10 solder, works great.

If you all thumbs, buy a new switch - not rewarding, but easier


luck,greg

 

Greg,

More good to know info. I was a aviation electrician and missile wire harness manufacturing engineer, as well as circuit board tech and reliability engineer. Any electrical that can be disassembled and cleaned is usually much less expensive then replacement, especially if the replacement is a cheaply made knockoff.

I have found a simple eraser can be useful for cleaning some contacts. There are also spray cans of dielectric contact cleaner that also work well. In the older airplanes, some relay contacts required burnishing with a burnishing tool similar to a diamond fingernail file. Fine sandpaper works also.

I especially like to know about things like replaceable brushes, and contactors as may be found in some alternators and other similar electrical devices.

A little disassembly and cleaning can go a long way.

 

I have the same issue on a 97 or 98 discovery. Headlights on on very low and instrument, tail lights on, in parking position, then interior and taillights go out when the switch is turned to headlight position.

What did you find out on why the tail lights and interior instrument lights go out when you switch headlights on? What wires coming out of the turn signal/light switch are the power and which goes to panel and tail lights?

I removed the switch and cleaned up the contacts. Not sure what is going on.

Any help appreciated.