Fog Light Rewire Problem

[supra90turbo]

Feel like a total noob here, but I rewired my foglights, and despite checking everything twice or more, they are not working as intended.

I followed dylan wiggins writeup, and even cross checked a few others, one other being by ish.

I did everything they did, down to the smallest detail (except, of course, the use of wire nuts) but only get fog lights when the parking lights are on, and only when the high beams are on.

I'm somewhat at a loss, I ran out of time before I could figure it out, and now it's going to bug me all night.

I'm sure it's something simple though.

Thanks,
Kurt


*links
dylan wiggins writeup
ish's writeup

 

[jetjock]

As poorly as that mod is thought out a quick analysis shows it should work assuming you have a later model year car. Based on what you said you've likely done something wrong with the red/black wire from the relay. You're lucky in one sense though: the write up I've seen for the 87 and 88 is a true abomination. Whoever came up with it should be slapped...

 

[supra90turbo]

Forgot to mention, but it's on my 90 so the colors should have all been right.

Oh, you've got that right, JJ... I feel that those writeups should be removed in favor of ones that encourage the use of correct connectors, tools, and common sense.
I used a lot of the wiring tips I got from you, as a matter of fact, I like my wiring to look and perform like factory when I'm done.

I used the guide simply for the wire colors, and, feel as if it were out of laziness considering I've got a perfectly good TSRM sitting on my toolbox.
I kind of feel like a moron now. haha

 

[jetjock]

Well, you must have screwed the pooch somewhere. Should be easy to fix though. The red/green from the fog switch picks up the white/black defogger ground while the red/black from the relay picks up the cig lighter feed at the fuse. Not the way I would have done it but stone simple nonetheless.

My problem at least with 87 write up isn't just in materials or connection technique. It's piss poor from an electrical sense. A really bad hack that shouldn't be done by anyone.

 

[RazoE]

with the 87 (which I did earlier today, thinking about another method though, since snipping and taping is not really what I'd like to do), you have to reground the relay, with 89+ you don't.

in simple terms what you're doing is re-grounding the fog switch, and then adding direct power to the relay..

if there were a better method, I'd like to know, since getting down there and wrapping fuses is a little iffy to me..


on a side note, make sure your bulbs aren't blown and your keys NEED TO BE IN THE IGNITION, and switched to on, otherwise you'll get nothing and feel like a fool...

 

[supra90turbo]

Somethings definitely fishy. I'm going to start from scratch, it'll be easier.
Everything checks out exactly as the writeups describe.

Yes, RazoE, my keys were in the Ignition and they were turned to ON. haha
I wouldn't be here asking if my keys were still in my pocket, I'd be far too ashamed.

It's just the thing that kills me, I'm no dummy, these things are always easy for me. Just checking to see if the writeup was flawed or if I did something wrong. I will post up my findings tomorrow. haha

Thanks for the help, guys. :bigthumb:

RazoE: Wrapping fuses, BIG no-no. I used one of these: Add-a-Circuit
Got it at AutoZone, made by LittelFuse and was only $5

JJ: Since you mentioned, how would you do it? I may do it my own way and was curious as to how you would do this. Everything I did is easily reversible, for sanity's sake, so if something like this happened, it would be a snap to get it back together to stock.

 

[jetjock]

The 87 mod is bad in that it defeats the fog fuse and transfers the entire lamp load to the tail light circuit. It also interlocks the fogs to the tails. If that's desired why not connect the fog relay to Intergration Relay #2 so you could still make use of the light auto-off function already built into the car? IR 2 is more local to the fog relay than the tail fuse (for key off) and connecting there would alleviate the need to even go into the left kick panel. Furthermore it would leave the fog circuit on it's proper fuse.

Or why not just skip that part of the mod altogether so the fogs can be run either with or without the tails and still have them go off with the key through the defogger feed? That approach is safer, also completely does away with messing around in the kick panel, and saves work. And while I'm at it tapping the cruise control feed would have been better. It's directly next to the fog switch on an 87 and has more appropriate fusing...

 

[gamer565]

That first guide is for a 89+, I found that out the hard way cause I tried it on my 87 and some of the wires didnt match up.


Follow the guide below, after I fixed my mistake I went back and did the one below and they work correctly now.

http://www.supras.com/06/techcenter/display.php?QID=41

 

[supra90turbo]

JJ: Yeah after looking that one over, the early rewire seems downright dangerous... Someone needs to remove those posts and rewrite them with longevity and safety in mind.

gamer565: My Supra is a 90.

 

[supra90turbo]

After much anticipation on my part, I couldn't wait to tackle this problem after work.

Turns out, I was wrong. I removed the red/green wire from the plug instead of the red/black.

I know exactly why I did that. When I was under there, I was upside down, with not much room to spare, and used the kick panel lamp as a flashlight, well since that bulb is green, it made the green stripe appear black on the 1/2" of harness that I could see..

So, I was lucky this time, but it could have been much worse.

Moral of the story, if you checked it once, check it twice. If you checked it twice, look again with a better flashlight.

Thanks JJ and RazoE for the pointers. The fogs look great now! I would have taken pics, but it was raining and the car was outside.

 

[Satan]

Gonna get back into mine today and check it out again. I used the add-a-circuit deal also and followed Dylan's write up (mine's a 91 auto dash harness). Used the Cig fuse and used 2 15a fuses in the holder...

Keeps blowing the AM1 40a fusible link in the engine-bay fusebox... even after pulling the add-on fuse out (both 15a fuses are fine). Finally stopped blowing the 40a one, when I disconnected the foglight wire from the Defroster white/black wire.

Looked simple enough and I really wanted to sport the fogs-only

 

[Satan]

Found issue in some previous wiring work at the foglight switch. Red/Green was making contact with a Green wire at the switch... shorting things out. Everything now wired correctly/good, but still no fogs. Cig lighter is getting power, but fog light switch is not getting power. F/L relay not clicking so replaced and still no click. I'm assuming that the short damaged something but can't figure out what... Frustrated.

Edit: I did try another F/L switch also. Still no fogs.

 

[Nick M]

My suggestion is you shouldn't do anything to the fog lights, but redo the relay which is low current. Leave the main circuits alone. I haven't read the 87, but what JJ said does sound really stupid.

Use the switch to provide ground to the relay. Minimal wiring. It could look similar to the Canada lighting. I think they have daytime running lights or something, and that was why their relay was powered the way it is.

 

[IwantMKIII]

^I attempted messing with the relay only on my early 89. Gave the same results as the op. Probably because I'm using an '88 wiring diagram lol (obviously i did not use it verbatim). I do know it worked well on my '88, simply switch when the relay is turned on and it yielded desired results, plus it only took about 5 minutes to do.

 

[Satan]

Without having to look at the wiring diagrams and getting upside down again 1st, anyone have the SPECIFIC info on how to do the 5-minute mod to switch the relay on when I want it to?

 

[Nick M]

Without having to look at the wiring diagrams and getting upside down again 1st, anyone have the SPECIFIC info on how to do the 5-minute mod to switch the relay on when I want it to?

Yeah, have the switch provide ground to the relay control side, and the power of your choice, such as the existing 15A fuse. Considering you could take 5 minutes pulling the interior pieces off and putting them on right in 5 minutes, it could take you a few extra minutes.

 

[SRZMK3]

or you could do my rewire style.... get an inline fuse wire and then put a 20 amp fuse directly inline and just wire the damn thing direct from battery positive and bypass everything.


hotwire in the middle plug i think fogs on the bottom remove the top plug flip the swtich and you have fogs on anytime you want

you may need to take the fogs out and wire them in series to the switch and just ground them on the chassis.

thats how i did it...

 

[shaeff]

or you could do my rewire style.... get an inline fuse wire and then put a 20 amp fuse directly inline and just wire the damn thing direct from battery positive and bypass everything.


hotwire in the middle plug i think fogs on the bottom remove the top plug flip the swtich and you have fogs on anytime you want

you may need to take the fogs out and wire them in series to the switch and just ground them on the chassis.

thats how i did it...

If you're going to do the foglight rewire, do it right. SRZMK3- I strongly suggest redoing your "setup" as it's set up for failure, in my opinion.

Hint: perhaps it has to do with the fact that the stock fog fuse is 15A, and you're suggesting a 20A fuse, thus allowing the possibility of fried wires, and the fact that relays are used to control higher amperage. Why would you want all that amperage running through a switch? Many cheap toggle switches can't handle 20A! I know that stock 55w bulbs are only going to draw around 9.5A? or so, but with taking old wiring into consideration, that could go up substantially with corrosion.

If you decide you can't figure out how to modify the factory setup to make it work, then rewire the fogs with a proper relay, preferably a relay with dual 87 outputs. (not 87/87a, that's different)

 

[SRZMK3]

fine, that means that the normal foglight kit you get from autozone is a failiure too then..

 

[shaeff]

You're really using an Autozone foglight kit as leverage? Yes, they're usually garbage.

Regarding the AZ fog setups: You'll get better output using a relay setup anyway, as the current doesn't have to go from the battery, all the way in to the cabin of the car, through the switch, then back out to the lights. With the relay mounted near the battery or in the engine bay, that's less of a distance (read: less resistance) that the current has to travel through to illuminate the lights, thus making the output better.