Dave, did you make any mod other than swapping in a 53?

This same issue affects local headlight relays for the same reasons. I'd recommend you try this fix (depending on year of your car).

Alan

Hi, I did not do anything other that swap out the Fog Light Relay, on my '85, '86 and an '86.5.

Dave

Thanks Dave! I'll give it a try. And BTW, I am pleased that my 3000th post is a "thank you". What a group.

So did the OP fix his problem?

Yep. Problem solved!!

I just had the same issue when installing LED's in my MY85 and swapping in a regular 53 relay solves the issue with the hi beams coming on when the fog lights are switched on.

Thanks, Michael and Alan. This (replacing the fog light relay with a 53 relay) is a nice, easy-to-implement, inexpensive modification that has the additional benefit of allowing all the bulbs up front to illuminate simultaneously.

I don't see any downside to this, other than perhaps slightly raising the possibility of cracking the lenses from excess heat if you're running all the halogen H3s (especially higher-than-stock ones) concurrently.

Hi, I just tried to install the LED H4 bulbs in my ex Japan 1990 ROW S4. Used Ed's caps and phillps chipped LED's.
Everything light wise is stock standard. Fog lights turn off if high beam selected.
Headlight switch assembly just dismantled and cleaned.
Main headlight relay fairly new.

I have a 53 type relay in position IV (fog lights). Swapped in new spare to make sure it was working.

As soon as I switch the fog lights on ( switch on pod pressed in, light switch turned to 1st or 2nd position) the headlights go to main beam and will not dip.
Normal function if I leave 1 halogen bulb in place or have the fog lights (pod switch) turned off.

Any ideas?

Myles

This does sound peculiar. My first thought would be to double check the relay position and make sure you are replacing the correct one. We all have been fooled more than once with the socket numbering. Look for the little arrow to indicate which direction the roman numerals are referring to.

The second course of action I would recommend is to replace the original relay and see if you can replicate the condition in the original post. That will give you a clue if your system is wired the same as my 88. As Alan indicated there were some model specific wiring configurations.

The next thing I would consider is try the system without the foglight relay. Does that solve your issue? Hopefully Alan can chime in since he seems to better understand the wiring variations for the different model years. Keep us informed

Oh one more thing, since your car is a Japan model, does your car have daytime running lights? IIRC, 1990 Japan and ROW cars had daytime running lights. Check out this post on the modification to enable this: https://rennlist.com/forums/928-foru...nger-cars.html

if your car has the DRL then maybe this is causing interaction problems. Try removing this relay for the DRL and see if you can get your system to work with the fogs.

Myles - do you have fear fogs? does their status (on/off) affect anything. The Japan configuration is a slight hybrid of ROW & USA.and has this different feature

Generally it seems the '90 is similar to the '88 for fog configuration... can you post a picture of your original fog relay (pin side view and part #)

Alan

Michael / Alan.
I have verified that I was determining the correct fog light relay position.
I do not have the relay for daytime running lights.
I do have rear fog lights. Their on/off status does not affect anything main light wise.

I will extract the fog relay and post a picture later today (it is dark out at the moment)..

Thanks

Myles

Photo of relay below. Part numbers / markings:
141 951 253B
22 300 007
WLO Germany
12V 40A
https://cimg8.ibsrv.net/gimg/rennlis...97bde961b1.jpg

Pin Layout:
.........--- ...............86
..---.......... | ....30 ........87
.........--- ...............85

Cheers
Myles

If your car came with a standard 53B relay in that position then its possible they swapped the wiring around and the 2 relays now are placed in reverse between USA/Japan and ROW...? that seems an odd change to make.

Can you check the 85 terminal in the fog relay socket - is it a permanent ground - or does it switch with the high beam? If it does switch with the high-beam - maybe you need the special relay removed by Michael above...?

Alan