RTH: Installed 4 to 7 pin tow/trailer kit and now NO headlights

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SoCal_80

SoCal_80

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I installed the converter from the factory 4pin trailer/light connection to the 7 pin round. It is a simple plug and play and then there is a separate ground wire. I grounded it to the frame as instructed. All looked well as i haven't connected the brake controller yet and just wanted to go get some gas tonight and notice d i have NO headlights at all (both high and low beams). So, i disconnected the 4-7pin adapter and still NO lights! I checked both fuses under the hood and all looks well. All other lights work, running, turn signals, dash, dome, etc.

This is what i installed and then unplugged:
37185_display.jpg


Oh ya, it is a '93 80 series...No Slee headlight harness.

I am at a loss and ANY help would be greatly appreciated!
 
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Short answer: I have no idea.

I would double/triple/quadruple check the fuses.

I'm not sure the exact wiring of the headlight circuit, but some headlight circuits have the current flowing through the switch (hence the use of relay harnesses). I suppose you may have fried the switch due to a short.
 
Ya, fuses look good (swapped one and still no joy).....
 
1973Guppie said:
I would check to make sure your headlight bulbs are still good and you did not blow them out somehow? see if you are getting power to the headlight terminals with a test meter.
Click to expand...

Thanks. I think/assume the bulbs are good since all 4 lights, low and high beams will not work..Could i have blown all 4 somehow ?

The trailer lights (i checked on 2 different trailers) all work...So not sure what i did wrong.

I did notice that the headlight relay is not clicking when i turn on the low or high beams nor does the high beam indicator show up on the dash. Does this point to any cause? I swapped the headlight relay with the same model# from my wifes 4Runner and still no clicking and no lights....Help...
 
I am no expert, but the first thing I would do is get a multimeter or cheap light current tester and test from the headlight plugs back to narrow down the possibilities. Check you have power to the headlight fuse as well. You can also continuity test (sp?) from the headlight back to the fuse block? I have heard of relays going bad, you could pick one up at kragen and swap it in to see if that is the issue. Like I said, I might be way off, but somebody will point out if I am on the wrong track hopefully.

Either way you are not going to figure it out unless you get a tester and start narrowing down the possibilities.

Noah

PS - test the relay, if you are getting power to it but not out the other side (switched on), the problem points to the relay
 
1973Guppie said:
I am no expert, but the first thing I would do is get a multimeter or cheap light current tester and test from the headlight plugs back to narrow down the possibilities. Check you have power to the headlight fuse as well. You can also continuity test (sp?) from the headlight back to the fuse block? I have heard of relays going bad, you could pick one up at kragen and swap it in to see if that is the issue. Like I said, I might be way off, but somebody will point out if I am on the wrong track hopefully.

Either way you are not going to figure it out unless you get a tester and start narrowing down the possibilities.

Noah
Click to expand...


Thanks Noah.
Ya, i already swapped the relay and no joy. Even with the new one i get no clicking out of it. The same relay in my wifes 4Runner clicks when the lights come on...in my 80....nothing.
 
SoCal_80 said:
Thanks Noah.
Ya, i already swapped the relay and no joy. Even with the new one i get no clicking out of it. The same relay in my wifes 4Runner clicks when the lights come on...in my 80....nothing.
Click to expand...

I doubt you fried the bulbs. Must be the switch if you are sure the relay you swapped is good. You can bench test the relay to verify it's working properly.

Check for power in at the switch then, turn on the switch and check for power out. You don't need to cut any wires just use the sharp probe from your meter to check for power and be sure your ground is solid.

If you have power out to the relay then you either have a bad relay or have wired it incorrectly. You can also temporarily bypass the relay to check the lights and switch.Sorry that's about it from behind the keyboard.
 
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gon2srf said:
I doubt you fried the bulbs. Must be the switch if you are sure the relay you swapped is good. You can bench test the relay to verify it's working properly.

Check for power in at the switch then, turn on the switch and check for power out. You don't need to cut any wires just use the sharp probe from your meter to check for power and be sure your ground is solid.
Click to expand...

Thanks..I will try the switch tomorrow.
 
Anyone know why simply plugging a trailer into the new adapter blew out my headlights? I am going to track down where the problem is but am now hesitant to try the trailer again.
 
I believe the bulbs are good, just not getting power to them (educated guess, but did not have a chance to put a meter on them this morning). Since the relay is not clicking, i am assuming there is no power going to it and thus to the headlights. When i plugged the trailer in to test the lights (which everything worked great) could that have blown out the headlight switch on the steering column? Anyone know a cost on that part? Anyone a electrical guru in So Cal? I can drive to your place, pay and provide beer, pizza, etc....
 
I'll be working in the driveway on a few projects today, if you want to swing by I'll PM you my cell and we can take a look at it. I'm no guru, but I've got a '95 W/Diag that might be close enough to chase down the demon!

Besides, I owe you one anyway, we used your driveway to put the springs and shocks in my truck :D


Dan.
 
If your taillights work and your headlights don't, sounds like you might possibly have blown the main FL, (fusible link).
You can test it by jumping across on each of the two wires. You'll find the FL off the positive side of the battery. It's a small black box with a two wire fusible link inside it. Open it and jump across from the positive side of the battery to the terminating end of each wire. The wires can look good but still have melted inside the covering.
Just a thought. Hope it helps.

John
 
SoCal_80 said:
I believe the bulbs are good, just not getting power to them (educated guess, but did not have a chance to put a meter on them this morning). Since the relay is not clicking, i am assuming there is no power going to it and thus to the headlights. When i plugged the trailer in to test the lights (which everything worked great) could that have blown out the headlight switch on the steering column? Anyone know a cost on that part? Anyone a electrical guru in So Cal? I can drive to your place, pay and provide beer, pizza, etc....
Click to expand...

I highly recommend you buy an inexpensive volt meter and read the instructions. You can buy decent meter's for under $20.00 and excellent one's for under $60.00 You don't need to be an electrical guru to understand and use your meter to check the basic's such as, is there power or not? Later on you can move on to testing resistance and other items. Your confidence diagnosing problems will skyrocket the more you use it.

I just noticed someone else recommended getting a multimeter as well. Here is a link on youtube for testing your relay. http://www.youtube.com/watch?v=3JB63ebFfgU
 
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sdcrzr said:
If your taillights work and your headlights don't, sounds like you might possibly have blown the main FL, (fusible link).
You can test it by jumping across on each of the two wires. You'll find the FL off the positive side of the battery. It's a small black box with a two wire fusible link inside it. Open it and jump across from the positive side of the battery to the terminating end of each wire. The wires can look good but still have melted inside the covering.
Just a thought. Hope it helps.

John
Click to expand...

I think the FL is a good bet - BUT, on my 95 diagram it looks as though the TL and HL share the same FL. So if the FL is blown, neither should work. This also makes sense as the trailer plug connects to TL circuit and only effects the HL circuit through where the TL branches off.

The also use the same switch, but in looking at the diagram, it seems unlikely you would have fried that with a short as that is not how the current would have flowed.

My only hesitancy on the FL is that the TL circuit is protected by a 15a fuse. I assume that normally would blow before the FL, but maybe not.

If it is the FL, you still need to find your short to figure out why the FL blew.
 
OK an update....It appears the no headlight issue may just be a coincidence.... The headlights began to work yesterday morning. I reinstalled my trailer work and all was still working...This is a good thing, right ? Today, I kept the lights on and they went on and off as i drove around town. I metered everything and when they are not working i am getting no power to my fuses or relay. So, as others have suggested, i think there is a bad connection near the main fusible link. I added the big Sears platinum group 31 battery a few months back and i think stretching the battery cable to the fusible link might be causing a bad connection...Does this make sense? Anyhow, i did not have time to investigate today but plan to look at the connection soon.
 
Sounds like you created a bad connection when you stretched the cable. I'm glad it wasn't related to the trailer connector as that's the same one I was looking at.
 
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