Fuse/Grounding Problem

Hi All,

Newbie here looking for a little help. I did a forum search and I found some folks with similar issues, but I'm not sure if mine is different at all. Driving a 03 Tacoma dlx, 4 cylinder, 2wd.

The other day while driving and using my turn signal they completely stopped working. Not the fast flashing or anything like that, just completely dead. My first thought was a fuse, and sure enough it was blown. I got a new one and put it in, and with the key turned, the turn signals worked. Start the truck up, use turn signals to leave parking lot and they go out again. At this point my 4 way hazard flashers work.

Had to get to work so I just went with it and used my arm as a directional. Now the plot thickens, it's now snowing when I go to leave work today: headlights work, but rear tail lights, brake lights, and high mounted stop light don't work, nor do my dash lights.

I make it home, but I used my hazard lights, and those stopped working on the way home too. I found that my hazard/horn fuse, turn signal fuse, and stop fuses were all blown.

Looking at the attached wiring diagram it seems like all of those ground to EA and IG.

My question is: is it just coincidence that all those fuses are blowing, and the turn signal fuse continues to blow, or is there a short somewhere in the system? Also, would a short at either EA or IG cause problems at the other and vice/versa, or would I have shorts at both ground locations?

I checked the bulbs, and because they worked with the 4 way hazards I figured they were okay.

Sorry for the essay length first post, or if this has been discussed in detail and I didn't find it in search results.

Any help would be appreciated as I'm not feeling so hot about not having brake lights or directionals.

 

Sounds like you have a short, 12vdc to Gnd. Those grounding points are just that and if they are corrosion free then that's not your problem. You do have something in common with all of issues you're having. On the turn signal issue remove each bulb and see if they could be shorted internally to gnd. Also take a look at your flasher circuit.

 

First I would inspect all the bulbs in the rear to be sure you don't have something melted in that area. With the bulbs removed see if you still blow fuses.

After that you're just going to have to pull out the ohmmeter to isolate where the short is. Each of these circuits that are shorting out shouldn't be too difficult trace. I was thinking maybe a loose wire behind the headlight switch or maybe something metal fell behind there because all the wires for the lights and turn signals are soldered near each other back there. I don't know how the stop lights fit into that theory. The stop lights going out leads more to a problem at the rear lights.

 

Thanks for the quick replies. I just replaced the blown fuses and put a fresh bulb in one of the front turn signals (which happened to have a broken lens). Started the truck, turn signal worked for 1 blink, hazards worked for 1 blink, and brake lights worked for one push of the pedal. I think my next step will be to look at all of the rear bulbs and check to see if any of those are fried, and I may look into picking up a turn signal flasher because they seem to only cost ~12 bucks.

 

Do you have a trailer harness on the truck??

 

Yes,,,,good question.

 

I do have a Curt T connector on the truck for 4 flat wiring. Think that would be a good place to start?

 

Yes,,,,,,,start looking from the connection going backwards.

 

Unplug the trailer connection box and see what happens

 

Well it was indeed the trailer light harness. Disconnected the T-connector from left and right tail lights, replaced the blown fuses under the dash and one under the hood and everything works with the truck on battery and while running.

Once it warms up I think I'll re-run the trailer light wires using split wire conduit to prevent metal contact and find good grounds as well protected as possible, unless ya'll think I should just get a new t-connector kit. Come to think of it when I was pulling my trailer this summer the trailer lights would only work if I had my headlights on.

Thanks for your help all!

 

The Tacoma's have a separate brake and turn signal that has to be combined to run the trailer. You have to have that little box.

 

The connector that I have (now disconnected) plugged into both rear tail lights and there was a box that I had to stick on the frame, with the 4-flat plug running out of that. But those wires don't have any conduit around them, so my guess was that some how a wire either melted or had the jacket rip off and was contacting metal somewhere under there

 

I know in other Toyota models (Land Cruiser, Tundra, etc. anything rated for towing) from that same era, they had a somewhat frequent issue with the convertor boxes(lil black box) melting inside. And thus the issues with the lights. I had this happen on an 80 series cruiser. New convertor box took care of the issue.

 

Also common to get moisture in them.

 

I would agree either a short or possibly a bad rectifier, just had to replace a rectifier one on a bike at my shop that kept blowing bulbs.

 

That's going to be the first thing I look at. The box really isn't in the greatest spot under the truck, so moisture could certainly be a problem. I'll update once it warms up outside and I get around to crawling under there and figure it out (no garage problems)