LED tail lights, non functional head lights, and other 1983 era truck wiring issues

[dwhyte]

After searching through this forum and many other toyota truck forums, hours of reading and re-reading wiring diagrams, and way to long spent continuity testing and staring at fuse blocks and multi colored wires I'm still at a loss. I realize it's unlikely anyone will be able to decipher what is going on without being able to look at it themselves, I'm at a total loss and any outside ideas would be super helpful

Long time lurker, first time poster, and I hate to make my first post a question, but I'm hoping this thread will benefit other too.

To start from the beginning with tail lights and turn signal issues, I'm renovating an 18 foot Sunrader and updating some outdated parts along the way. The old bargman triples were basically wrecked so I decided to go all the way and replace them with 4.5" round led tail lights. I fiberglassed the old holes and wired in 4 round tail lights. They're combination stop/tail/turn lights with only connections- 1) ground 2)stop/turn 3) tail, so I have them wired with the turn signal wires and stop wires spliced together and then into the tail lights. The brake lights and running lights work fine, but when you hit the brakes both turn signal indicators light up on the dash (which I expected because the wiring is connecting the two). The problems begin with the turn signals not working at all, and neither do the hazard lights. When I turn the turn signal switch either direction and turn the hazards on the hazards will work.

At this point I'm thinking it would be easier to re-wire a new flasher relay given that the LED tail lights are going to blink fast anyway, but I would like to use the existing fuse block and turn signal switch, I'm just not sure which wire coming from the steering column is the power coming in and which wires go to which lights... if that makes sense.

The second issue I'm having is the headlights no longer working. If I turn on the headlight switch, all my clearance lights come on, the new tail lights come on, but the headlights will not. I currently have them wired into the accessory wire so that when the key is on the headlights are on and with it set up this way the brights work from the switch as well, but I would like them to work as originally designed if possible.

I'll leave it at that for now, and any help or tips or ideas would be greatly appreciated.

[Bob C]

On my '88 Escaper I have separate brake lights and turn signal lights. You can do the same thing by using one (each side) of your rear lights as turn and the other one as brake. You currently have power going to the brake lights and then going to your turn signal circuit. If you turn on one turn signal I would think that all of your turn signals are probably going to flash.

Separate your rear lights by having every fixture wired to your tail lights (dim), outside fixture (bright) wired to brake light, and fixture toward the center wired as turn signal (bright.)

When I wired my RV for trailer lights, or lights on the back of my luggage carrier, I had to put in a 5 to 4 wire converter. You could also add one of these instead of separating the fixtures.

[dwhyte]

Thank you for the reply, I did what you suggested and it worked, I now have blinkers, brake lights, and parking lights in the rear. I noticed that semis with LED tail lights like mine are wired the same way when I went to pick up some resistors, and the more I think about it, the more it makes sense given that incandescents that have a brake and turn signal in a single lens are dual filament.

Still trying to work out the headlight issue. When I turn the headlight switch on everything works like it's supposed to except the headlights unless I run a hot into the headlight fuse the only thing I can think to do is wire them in with the tail running lights in order to get them to turn on when they're supposed to, but I don't want to overload that circuit.

[5Toyota]

often times the headlights were on a fuse link from battery positive to a connection near the battery

[waiter]

The stop lights and turn lights are on separate circuits. When you wired them together, you basically tied all that together, Anytime you turned on a turn signal, both left and right probably came on, and if you hit the brakes, the lights cam on but now you couldn't see the turn signal blink.

You want to electrically combine the stop and turn into one circuit, Two ways to deal with this.

1) Use one of these converters. This will combine the stop and turn into one circuit. (Drawtight # 119130)

2) I drew a diagram that uses diodes to combine, the problem is, if you have a turn signal on, and hit the brakes, the light will be on all the time as its getting its signal from the brake circuit. This would probably be acceptable if it was a trailer, but not acceptable for the main vehicle. Use the converter, they are less than $20 bucks.

John Mc

88 Dolphin 4 Auto

[fred heath]

Headlights: First check that you have voltage passing through the fuse. (sometimes the fuse can be bad even if it looks good). On my toy the power to the headlights comes from the battery (hot all the time).

Next, as 5Toyota mentioned check the fusible link under the hood. You should have two of them. One for the fuse panel and one for the headlights. The headlight will probably be the smaller of the two wires. Finally, check your ground wire for the headlights. A bad ground will cause them not to work.

[dwhyte]

Waiter, thanks for the link to the converter. I'll probably go that route eventually, but for now I'm happy with splitting the stop and turn signals to different lights given that I have 4.

As for the headlights, I don't have power to the fuse at all, not when the truck is on, or off, or the switch is on, or off. I have run a hot straight from the battery to the head light fuses, but that just causes the headlights to stay on all the time, which is why I currently have it wired to the accessory switch so that at least they turn off when the truck is off. A bad ground seems like the most likely culprit, but I'm not sure where the headlights ground to.

Thanks again for the help, once I have some time to collect the pictures and put them online I'm planning on posting a thread in the renovation forum for everyone to see it!

[fred heath]

Dwhyte,

If your headlights work from the battery, your grounds are probably fine. It sounds like its probably in your fuseable link, or the line running from it to the two HL fuses.

You could also have a bad headlight relay.

My suggestion is to buy the Haynes manual for your year chassis. I prefer Haynes over Chilton as it gives you the wiring diagrams in the back. Chiltons doesn't. It makes trouble shooting electric issues much easier. Good luck. Fred

[dwhyte]

I actually have the haynes manual, and no matter how long I sit and look at those diagrams I can't make them relate to what I'm staring at in the tangled mess of wires under the dash. The previous owner did some really odd wiring (like having 3 inline fuses running to an extra 12 volt outlet they installed) so I'm slowly untangling it all and figuring out what exactly goes where. I started out with a vehicle that would only start if a jumper cable was run from the positive battery post to the starter solenoid due to a poorly wired and completely destroyed main relay. What I'm trying to say is I work better tracing and testing wires and drawing my own diagrams than reading the manual I guess.

I do think you're onto something with the headlight relay though, or the possibility of the problem being in the fuseable links or the wiring in between. It seems like the only place left it could be. I'm coming down to the wire (pun intended) because once my lease ends at the end of the month I'll be moving to Colorado from Arizona with my girlfriend and dog and we'll be living in it while we look for a new place. So again, thank you for all the reply's and help, once it's all said and done I believe this will be an awesome rig/project/money pit for years to come.

[Boots]

Hi,

I too had trouble with the rear lights, and in the end fix them, the reason for the failure - originally the Toyota / RV coach manufacturer used unusually small wires for the grounding. I trace the circuit from the from the front to the back and eventually located at the rear, just before the wiring harness splits into left and right rear lights. All I had to do was to install a new ground wire, from each of the tail lights, and fasten them to the frame. Problem solved.

As for the headlights, you have either a relay or fuse problem. Headlights are heavy consumers of power, and are controlled by a single or double level relay. The only other place they come into effect, in some models are daylight running, which may be grounded.

Boots

[Maineah]

What year is your MH?