Fog light gremlins

[jeepdoggydogB]

I am having some foglight issues on my 1991 and I am only finding one relay by the airbox, and it tests out good. My question is, isn't their supposed to be two? One for the headlight and one for the foglights? The one relay tests out good, and the fuse in the PDC tests out good yet I get no power to the foglight pigtails. The harness and foglights are factory BTW.

Thanks!

Joe

[offroader461]

no there is only the one foglight relay near the airbox..BTW the foglights only work when the headlights are on

[jeepdoggydogB]

no there is only the one foglight relay near the airbox..BTW the foglights only work when the headlights are on

Thanks! So there is only one relay by the airbox? The funny thing is with the fog switch on and headlights on the fog switch does light up, head lights also are good, but no fog lights. There has to be something wrong with the pigtails maybe?

[offroader461]

hmm i went nuts on mine...only way the fogs would come on is if i had the headlights on and then flipped the foglight switch on and Viola they were on....id check the ground

[HOrnbrod]

offroader461 is correct, there is only one fog lamp relay. Zero headlamp relays. The fogs only come on w. low beams in the factory circuit configuration. Turn your headlamps ON low beam, then turn the fog lamps ON while you listen (or have someone put their hand on it) for the fog lamp relay click. If it clicks, the relay is most likely good and the problem is further out toward the fog lamps.

[jeepdoggydogB]

offroader461 is correct, there is only one fog lamp relay. Zero headlamp relays. The fogs only come on w. low beams in the factory circuit configuration. Turn your headlamps ON low beam, then turn the fog lamps ON while you listen (or have someone put their hand on it) for the fog lamp relay click. If it clicks, the relay is most likely good and the problem is further out toward the fog lamps.

I did try that but I must admit I didn't try it with someone putting their hand over hte relay I took the easy way out and picked up a new relay at autozone which yielded the same results (no fogs). I will try the relay test, and if it fails try to trace from the realy to the fogs.

Thanks Don!

[jeepdoggydogB]

Well the realy definitely clicks, we have power to the aux lighting fuse in the PDC, so now the down and dirty part of tracing the problem from the lights to the relay.

[mvusse]

This might sound silly, and don't be offended, but:

 

Did you check the bulbs?

 

Years ago I spend a week trying to find an electrical problem with my headlights before I realized both bulbs had burned out. :oops:

[jeepdoggydogB]

This might sound silly, and don't be offended, but:

 

Did you check the bulbs?

 

Years ago I spend a week trying to find an electrical problem with my headlights before I realized both bulbs had burned out. :oops:

Haha not silly at all, there isn't any power to the factory connector at the lights when the foglight switch is on and the headlight low beams are on, and the relay has "clicked".

[jeepdoggydogB]

OK I think I figured it out. I am using the Bigoffroad wiring harness, I noticed that a few months after I installed it, I was not able to turn the low beams off until I turned the vehicle off. big offroad wiring harness runs the headlights off of battery, and has two relays, high beam and low beam.

 

I pulled out the relays and they have gotten green corrosion all over them. My theory is that the low beam relay is not working properly hence not sending a signal to the foglight realy telling it the lowbeams are on. I hear they sell these relays at Napa, I will replace and let folks know what I find out. :eek:

[HOrnbrod]

OK I think I figured it out. I am using the Bigoffroad wiring harness, I noticed that a few months after I installed it, I was not able to turn the low beams off until I turned the vehicle off. big offroad wiring harness runs the headlights off of battery, and has two relays, high beam and low beam.

 

I pulled out the relays and they have gotten green corrosion all over them. My theory is that the low beam relay is not working properly hence not sending a signal to the foglight realy telling it the lowbeams are on. I hear they sell these relays at Napa, I will replace and let folks know what I find out. :eek:

 

Why don't you just bench test the suspect relay? Use a 9V battery or a battery charger across the relay coil terminals (usually contacts 85 and 86), and an ohmeter across the NO (Normally Open) load terminals (usually contacts 87 and 30). If the relay is working you will get continuity across the load contacts when you apply power and the relay latches. Unless you just want to buy a new one. :D

[jeepdoggydogB]

OK I think I figured it out. I am using the Bigoffroad wiring harness, I noticed that a few months after I installed it, I was not able to turn the low beams off until I turned the vehicle off. big offroad wiring harness runs the headlights off of battery, and has two relays, high beam and low beam.

 

I pulled out the relays and they have gotten green corrosion all over them. My theory is that the low beam relay is not working properly hence not sending a signal to the foglight realy telling it the lowbeams are on. I hear they sell these relays at Napa, I will replace and let folks know what I find out. :eek:

 

Why don't you just bench test the suspect relay? Use a 9V battery or a battery charger across the relay coil terminals (usually contacts 85 and 86), and an ohmeter across the NO (Normally Open) load terminals (usually contacts 87 and 30). If the relay is working you will get continuity across the load contacts when you apply power and the relay latches. Unless you just want to buy a new one. :D

Thanks! Does that type of test work on these four lead relays?

 

http://www.napaonline.com/MasterPages/N ... +Relay+Kit

[HOrnbrod]

Yep. Find the two pins that have the least resistance, like 10 ohms or less with your meter. That's the coil pins. Apply the 9V battery across these pins, the relay should click and the other two pins will read continuity.

[jeepdoggydogB]

Yep. Find the two pins that have the least resistance, like 10 ohms or less with your meter. That's the coil pins. Apply the 9V battery across these pins, the relay should click and the other two pins will read continuity.

Thanks Don, test worked great, replaced bigoffroad relay and now my headlights function normally (turnoff when headlight switch is postioned to off), but my theory was incorrect still no foglights. :mad: