Hey guys, I've been searching around the site and found a few threads on this phenomenon but want to ask and get some opinions as well. As you can see in the video below my headlights and fog lights flash. This starts up after about 30 minutes of operation whether the car is driven or stationary. It only involves the headlights and fog lights, no issues with maker lights, gauge cluster or taillights flashing. The flashing will go on for about 3 or 4 minutes then normal operation for about the same amount of time and then back to flashing. Headlight switch was recently replaced. Could the fog light relay be on the fritz? Can't seem to locate the fog light relay in the drivers side corner area of the engine bay as is the case with some cars but then mine is an '85 Camaro. Does anyone know where the fog light relay might be located in an '85 Camaro? Thanks


VIDEO OF HEADLIGHTS FLASHING

 

Did it do it before the headlight switch was replaced? If it were the fog light relay, the headlights wouldn't be cutting out. Regardless something in your headlight circuit is overheating and causing the circuit to open. When it cools it completes the circuit and the lights come back on, until the weak link heats up and breaks the circuit again.

Get a wiring diagram and start troubleshooting. Check the fusible link that powers the headlights. Check your grounds. Study the headlight switch on the diagram and determine what could effect just the headlights and foglights and inspect those parts of the car.

You might also check the symptom table in the factory service manual for the problem you're having and follow the guide to resolve the issue.

 

Thanks Drew, yes we replaced the headlight switch because of the flashing hoping that was the problem. At some point after it began to flash I turned off the headlights momentarily, then back on and it seemed to stop the cycle of flashing for about 5 minutes but then it returned. I then turned the headlights and fog lights off and turned only the headlights back on. After ten minutes there was no flashing but unfortunately I had to leave and ended the test. I'll try leaving off the foglight switch off again today and test to see if the flashing returns, otherwise I'll dig further into it as you suggested. Thanks a bunch.

 

Are you running sealed beam conversion headlights with high power bulbs?

 

No, just standard sealed beam HL's

 

I have a question for you ;

When you say "flashing" , is this flashing erratic , as in the lights are flickering with no distinct pattern (possibly from a frying connection in the circuit , for instance) , or is this a very distinct off-on off-on with a steady rhythmic pace ?

If it's a steady blink akin to how a regular turn signal works (but with perhaps a different rate of flashing) it means the headlight circuit is drawing too much current and the built in , self resettable circuit breaker contained within the headlight switch is being activated .

 

see below

video of headlights flashing

 

Yes , that is the built in circuit breaker cycling , your drawing too much current in your headlight circuit . In this drawing they depict the thermal breaker as a curved wire between two dots at the top left side of the switch . Now , as to why you may be drawing too much current there could be several reasons , I'd like to ask , did this problem just suddenly appear with no work having been done to the car's electrics ? As in , were the headlights changed (even if they weren't changed with stronger units) ? Were the foglights worked on , especially the foglight relay ? I have a suspicion about the foglights but I'll wait to hear your response to whether any electrical work was done (except for the new switch which I know you said was an attempt to fix the problem) before I describe what I'm thinking about the foglights .

 

Thanks for the help, yes I had a new auto adjusting dual cooling fan unit installed at the same time as this issue began. The installer brought it to my attention after he test drove the car after dark. He replaced the headlight switch believing that was the issue but now my concern is he might have made a incorrect connection while installing the fans. We both believed the issue had been resolved after the new switch was installed. The fan installer notifying me of the flashing headlights was the first time I heard of the issue. I rarely drive the car at night and the few times I have were not for an extended period of time and as I mentioned in my first post the flashing begins after 30 minutes of operation. I'll follow your advice and see what we find, thank you!

 

Wow , interesting news about the electric fans , good God hopefully he didn't wire them into the headlights ....

Now , here's what I was thinking with regards to your foglights ;

If you look at this wiring diagram (I know it says 1992 but I'm fairly certain the foglight circuit didn't change through the years) you will see that the foglights are a complete stand alone entity from the headlights , they don't get their power from the same place the headlights do , and only get a ground for their relay's coil through the high beam filament when the high beams are off (The small upside down triangle at the bottom left of the drawing . This is what kills the fogs when you switch the high beams on , the loss of the ground that was the cold high beam filament) . To put it simply , in the factory wired configuration your foglights shouldn't be going out and coming back with the headlights , unless they are somehow miswired to be taking their power from the headlights instead of from their own separate dedicated power source (the foglight fuse) . In short , if your fogs ARE taking their power from the headlight circuit somehow (bad wiring , etc) the excessive draw of those fogs on the headlight circuit would be a pretty good reason for the circuit breaker to trip ....

 

Problem solving 101...

Q1: What changed prior to the problem showing up?

A1: Cooling fan modification.

Q2: The 30 minutes that pass before the problem starts; is this the approximate time it takes the fans to come on?

A2:

 

Q1: What changed prior to the problem showing up?

A1: Cooling fan modification.

Q2: The 30 minutes that pass before the problem starts; is this the approximate time it takes the fans to come on?

A2: No, fans come on before the flashing, once the car comes up to temp. I still think the fans are involved so that's second on the list of wiring to look at.

 

I think you’re on to something here logically... It would seem the fog lights would be more tied into the marker and tail lights given they come on with the half pull of the headlight switch as well. The headlights only come on when the switch is all the way pulled..

Didn’t you have to replace the fog lights in this car?

I’m wondering if whoever did that job did tie them into the headlights somehow. Perhaps the aftermarket fog lights were wired differently for some reason and putting the stock fogs back in the wiring wasn’t stock...

do the headlights flash when the fogs are off?

 

Yes the fog lights are new and I replaced them, but I wired them into the existing wiring that was powering the old after market lights. Not sure if this matters but in "85 the fog lights only come on with the headlights (low beam) unlike later models where the fogs come on when running the marker lights alone. Yes the headlights flash with the fogs turned off. I may try to disconnect the fog lights and check to see if there is any difference.

 

I didn’t know that about 85 cars... I only had an 85 Z28 so no fogs on that one...

 

Hi GASPEDDLER , if the headlights flash with the fogs turned off then the fogs aren't the problem . Something is drawing too much power in the headlight circuit but you'll have to look elsewhere from the fogs . Also , if the new electric fans run without the headlights on , it's not going to be fans . Were they miswired into the headlight circuit downstream of the headlight switch circuit breaker , they would need to headlights to be on to run , and it doesn't sound as if this is the case here .

 

Thanks for all the help guys, it really helps to eliminate items which would not be factors before starting to dig into it.

 

The headlights can come on when the car is in the “off” position though, so wouldn’t someone be able to tie into the power going to the headlight switch and complete the circuit without the switch being on? Sounds like a bad idea but might have happened. The headlights can turn on without the car being on as well which is the same with the fans, correct?

Hope you find the solution and post it up!

 

The fans do remain on for about 30 seconds after the engine is shut off in order to continue cooling off the engine and then turn themselves off.

 

Hi 88IROCvertZ , The circuit breaker that I believe could be flashing the lights is built into the headlight switch itself . If someone connected a wire to the wire feeding the headlight portion of the switch , that additional drain wouldn't be seen by the breaker since it would technically be before the switch , and therefore unable to overload the breaker . The overload would have to be on the "cold" side of the switch , the "switched side" in other words , which is the yellow wire leading from the headlight switch in the first drawing I posted . This wire is only powered when the headlights are on .

If it is the breaker , I wonder if the lights themselves are drawing too much power ? In the video the lights look very white to me , and not the duller yellowish look of what I remember the stock sealed beams to look like .



It's voltmeter time ! (or even a decent 12V automotive test light) At this point , the best diagnostic I could suggest would be to put a voltmeter on the yellow wire in the first drawing I posted and see what happens there when the lights go out . Does the +12V go away or does it stay ? A handy place to probe this would be at the highbeam switch . If it goes away you'll have to check the red wire leading into the switch from the fusible link to see if it remains on there when the headlights go off . If perchance the yellow wire still has +12V when the lights go out then it wouldn't be the circuit breaker in the headlight switch tripping and the next check would be at the tan wire leading away from the high beam switch to see what's happening there , if the yellow doesn't loose power but the tan does then the problem would be the highbeam switch (checking the tan wire because in your video it is the low beams that are blinking) . If the tan wire does remain with +12V when the lights go out now you'd be looking at a possible connector problem , since there isn't anything but connectors and wires between the highbeam switch and the headlight bulbs themselves . By a method of divide and conquer , find out where exactly +12V is and isn't in the circuit when the lights blink , and this will lead you to the problem .

 

True... when I’ve driven my IROC at night (a few times) which may even have the original sealed beams or sealed beams from the 90s they are so dim compared to new cars... almost look like old flashlights on the road... Those lights do look bright...

Seems like it has something to do with the fans though... that’s my gut feeling based on the info and timeline of symptoms...

 

 

Maybe I should try some of those out so I can actually see at night..

 

I know , I'm right with ya , I've got Sylvania silverstars in my car and they don't look as bright as in GASPELLDER's video . They must just look that bright because of the video I guess .

Anyway , I have nothing else to offer here except that GASPEDDLER should try taking the voltage measurements I described in my previous post , those will be key to finding out exactly where the problem is ...

 

I've got to wonder if the aftermarket lights were wired in with a relay or not ( probably not. )

The 85-87 used a fog light set-up that was very independent of the other wiring in a Thirdgen & in 88+ the fog light set-up was changed so the wires were incorporated inside the Engine and Dash harnesses. If someone added aftermarket fog lights to the car than it should have been wired similar to the 85-87 set-up.

Here is the schematic from an 85: ( 86-87 similar,.... I think the BROWN 'headlight signal' wire to the relay was a different color. )

 

Thanks guys, I won't have time until the middle of next week to look at the car, but I will check back when I do and hopefully when I find something.

 

Hi John , GASPEDDLER says that the headlights flash with the fogs turned off , so the foglights , aftermarket or not , should not the problem .

 

Don't get hung up on the circuit breaker in the switch. Anything in the electrical circuit can overheat, break the circuit, cool down completing the circuit, and repeat. Like I said before, look at the wiring diagram and start where the circuit gets it's power, most likely a fusible link, and work thru the circuit to isolate the issue. It could be a loose ground wire, or a corroded contact, broken wire, flaky switch, etc. Just gotta think it thru logically, visually inspect what you can, eliminate possibilities, test what you can, and narrow the problem down until there are fewer possibilities.

 

Yep , Both Drew on post two and I on post twenty both agree it's gotta be gone through with a meter (or test light) to determine where the power disappears . I freely admit to not being 100% convinced myself of the belief that it is the breaker due to how random the blinking becomes the longer it's left to blink , this will be an interesting one for sure once found

 

Here are the 87 Camaro diagrams and diagnostic charts.

 

Hey guys checking back in as I finally sorted out my flashing headlights. We found the yellow wire running between the high/low beam switch and the headlight switch was down to only two strands of wire where it connected to the headlight switch! The switch was getting really warm and I assume the circuit breaker was cutting out the headlights because of that. We went through and sautered up all the connections. I drove the car around this evening for two straight hours and the headlights performed flawlessly. I did notice the gauge cluster is not lighting up and adjusting the dimmer switch only seems to adjust the transmission gear selector and toggles the dome light and courtesy lights below the dash. Adjusting the dimmer switch does light up the gauge cluster momentarily but it does not stay illuminated. I’ll pull the switch again tomorrow and recheck my connections. Thanks for all the help guys!

 

Wow... interesting!