. I've run truck lights 7" round LED plug and play system for 2 years . They work well with one exception. When I turn on the fog lamps the left high beam side flickers and eventually both high beams come on. This o key happens with fogs on. I installed the CREE fog lamp H3 projectors today. No change. Also my replacement led brake light bulbs leave the brake light test light on all the time. I'm planning on converting many more bulbs to LED but need to solve these two issues first. I'm wondering if I'm getting some feedback on the lighting circuit causing the flickering. Ideas?

 

its all has to do with the resistance in the wires and relays. the bulb checker thinks the bulbs are bad. have you added the resistors inline to the bulbs? just like how turn signal relays blink fast with LED's....?
check the light switch connections for corrosion and feedback.

 

Clean your grounds?

 

I doubt its "feed back", more likely a failing switch/relay.

As for the LED Brake Light, you will need to defeat the Lamp controller (mounted on the right side of shelf).
There is a wire that comes from the brake light peddle switch and goes into that controller and you need to by-pass the controller.

Run a wire directly from the Brake Light Switch to the Brake Lights feed(power) on the LAMP Controllers connector(the output of the lamp controller).

This can all be done w/o cutting and or destroying the stock wiring as pins can be removed from the connector.
I'm running all LED's so I no longer have the connector plugged into the Lamp Controller and use Jumpers to defeat the others and the Brake light feed wire as described above.

Note: I also do a walk around as a "manual" lamp check

Dave

 

Good general principle: Anytime that automobile electrics start doing weird things, clean all of the grounds.

In your case: If you apply power to the fog lights, the fog light power will travel thru the light, then down the ground wire to the ground stud, where there are also ground wires from the headlights. If the ground connection at that point is bad, it is possible for the fog light power (which will get to a ground connection in any way possible) to travel back up the ground wire to the headlight and make it burn (perhaps with less than full brightness), then travel thru the light system until it finally get to a ground.

Checking and cleaning grounds is free, and is virtually never a bad thing.

 

At Idle, one of the headlights will flicker its high beam array while the other side headlight is on low beam only. If I run the RPM up above idle both Highbeams come on and the fog lights cut out. Its almost like the high beam/low beam switch on the column is being over ridden when the fog lights are on. IE... the power from the fog lights is turning on the high beam array's in the headlights. I even get a dim high beam indicator lit up on the IP. If this isn't due to need for resistors in the line from the headlights then I am voting for a bad headlight switch. I did replace this one with a used on the day I bought the car. It was bad. I also have the NASA cruise control option (hit the cruise and you get full throttle blast off). Is there some way to test the multi-function switch? I am voting for a bulb removal from the IP where the brake bulb warning is.

 

I installed the led bulbs in the turn signals. The flasher only goes off after three seconds. Should I replace the flasher with an electric led flasher?

 

I ordered balast resistors today. Talked with tech line for the bulbs. They told me this is the solution

 

Yes you need an electronic timer flasher - the bimetalic switch types rely on the higher current from the 21W turn signal bulbs.

Alan

 

Tried an electric flasher unit. It didn't help

 

and how are the grounds?

 

That's odd about the electronic flasher. It is a chip controlled timer circuit, that cuts power to the lights on a preset timer program. That it would stay on for the same amount of time that your mechanical flasher is really odd...next to impossible. Are we sure we got an electronic flasher, and not another thermo-mechanical relay by mistake?

On the headlight issue, it seems that you are telling us that the headlights work normally in every way, provided the fogs aren't on. Is that correct? They flash to pass, they dip high to low, they come on without flickering?

Also, if the headlights are already on in the normal low beam position, and you then turn on the fog lights, do you still have the high/low beam flickering...on just the left light?

Normally here in the USA at least, the fogs dont come on except when the high low relay is spring loaded to the low beam position. (but I think they are used in the flash to pass mode if the lights aren't on...I think)



It would seem odd that the fogs would power up the high / low relay causing the lights to switch to high beam. More odd still is that since the high / low relay is connected to both right and left at the same time, that one light could behave independently from the other (that is, one light flickering and the other not).

With the fogs off, do they flicker when you switch from low beam to high beam?

Here's why I want to be sure, sometimes in troubleshooting over the internet, a single word, or a multimeter one click out of position (that we woulda seen in person), can throw us off in an entirely new direction.

I'm not smart enough to troubleshoot this issue from here in the great state of Texas, but perhaps I can help with some questions, and basic descriptions that might help you or someone else have an idea.

The master headlight relay performs several functions. 1 is to start the pop-up motor, 2 is to supply power to the headlights (through the high/low relay), and 3 is to switch between high and low beams.

the portion that switches high and low beam acts on both lights at the same time.

Aside from wiring, the only thing independent of the left (flickering) headlight and the right headlight is their individual connections and their fuses and of course the circuitry inside each bulb.

There is one other thing, the fog light relay can be powered up when the lights are off by the flash to pass circuit. They can also be powered up by the normal means of ...tuning them on. the "on" signal from the flash to pass (which hits the high beams when the lights are on) and the regular "on" signal share a connection to the relay. the reason that the signal from the regular "on" signal doesn't travel back through the shared connection to flash the high beams is a diode. a one way valve for electrons. It is located within the fog relay, if it were shorted, tuning on the fogs through the normal means, COULD POSSIBLY go through the shared "flash to pass" connection and hit the high beam relay, which would normally only get the flash to pass signal when the lights are on and popped up.

Ya might look there at the fog light relay.

Ya might also consider that a shorted diode will be a poor but passable connection and MAYBE cause a flickering in a lamp that already has a poor connection.

Also, the Left headlight line powers the blue indicator on the dash pod, does it flicker (if it does, perhaps the problem is on the line, if not maybe in the lamp itself).

That's all I got. No promises, or guarantees.

 

You are correct in description. I've contacted the manufacturer and described my issues. They tell me to put a load resistor in the line. I ordered plug and play line resistors for the headlight and resistors for the brake and turn indicators online. That's my next step. I tried a LED electronic flasher and it did not work. There must be something unique to our flasher. I tried a spare flasher unit same part number I have in my stock and the result is the same.

 

Make sure you get the electronic flasher with the correct pins on it..there are a couple of different versions out there. I bought mine from SuperbrightLEDs.com and it worked perfectly on my 86.5. The first electronic flasher relay I tried did not work because the pins on the relay were not the same as our 928 relays...second time around I got the correct one, and it worked. As mentioned, the company above knew which one to use. Unfortunately I passed it along to another Rennlister so I can't send it your way.

Cheers!
Carl

 

I ordered another relay for the led turn signals. But the brake light warning would have me getting into the wiring in the back under the rear quarter windows to Install resistors. How hard is it to get the rear bumper cover off instead.