[TSTONE]

tail light problem


I'm having a problem that I can't track.

It's a std 2 wire setup. The brake lights work when the headlights are off (I checked and have 12v at the 1st wire on both sides), when the HL's are on the brake lights stop working and the tailights don't come on (I checked and have 12v at both wires on both sides). When I let off the brake with the HL's on the taillights still don't come on (I checked and now have 12v at the 2nd wire on both sides). So i'm uber confused cause according to the vt meter everything should be working??? I have tried multiple bulbs to make sure no internal bulb shorts.

Help?

??

 

[SixtyAte]

Bad sockets or bad ground. Try grounding the socket with a brick or someone pressing on the brake. You should find what is wrong doing it this way. Also be sure that the bulbs are in properly.

Kev

 

[TSTONE]

what do you mean by grounding the socket?

as for the bulbs they are definitely in properly and have tried multiple bulbs

 

[dnult]

The bulb sockets should be grounded through a short pig-tail wire that connects to a ground point in the trunk near the latch. I think what Kev is pointing out here as that dual filament bulbs can provide alternate ground paths if your official ground is not healthy. In a dual filament bulb, you've got one bright filament and one dim filament connected together in series with a ground point between the two. If the ground is bad, the dim filament can provide a ground for the bright filament making them appear to work OK when the lights are off, when in reality they aren't working OK. When you turn on the lights, you've got 12 volts appied to both filaments so no current flows.

I agree that grounding is probably the problem here. Could be as simple as a bad ground at the negative battery post to right fender connection.

Use a volt meter to measure the voltage drop across various ground connections. Your meter reading should be less than 0.01 volts in most cases (with the circuit powered up). If it's more than that, you've got a bad ground. It might be necessary to extend one of your meter leads with a piece of wire having an alligator clip on each end. An extension chord can be rigged up to work also.

 

[TSTONE]

I think i'm going to officially turn in my man card.

Sorry to trouble everyone - I have found out that self grounding sockets work much better when you install them into the tail lamp housings that they are supposed to ground out on (right here is where i'm banging my head on the desk repeating over & over, "stupid-stupid-stupid"). thanx for the quik responses - and i'm just going to go over here in the corner and be quiet now.

 

[dnult]

LOL...humility is a trait of manhood. A great deal of experience comes from LAFU (learn as you foul up). Glad it was an easy fix, aren't you.

 

[SixtyAte]

.

I have found out that self grounding sockets work much better when you install them into the tail lamp housings that they are supposed to ground out on

No problem..you are not the first one to forget something while working on their car Go easy on yourself...glad its fixed.

Kev

 

[fearsomfoe]

I had this same problem after a complete rewire! Turns out that I had the two wires on the brake light switch backwards. I just flipped them around and it fixed it!This didn't make any sense to me but it worked.:noway:

 

[Johnny B]

Man Card!! LOL, I have never heard that!!! :thumbsup: