So the engine compartment fuse #22 10amp, keeps blowing. It is for small lights, which I have so far identified as being all rear normal lights, plus license plate.
I removed all bulbs, still blows
Not sure where the short circuit is, or what else runs of that fuse.
Any ideas, advice?
Thanks
Michael
Fuse #22 also supplies power to the tail light relay and the relay control module. Both are located in the same fuse box.
Tester
Unfortunately, I don’t have any data for that. That fuse most likely supplies power to the front running lights also. The rear license plate light is a pretty good possible suspect, where the wiring runs between the body and the rear door. Hopefully the trouble is happening all the time and isn’t an intermittent problem, which would really make it difficult to find.
If the trouble is constant you can use an ohmmeter to monitor the protected side of the fuse position contact and ground to watch the resistance change as you disconnect various harness connections and watch the resistance changes. You can also substitute the fuse with a brake light bulb wired across a blown fuse and watch the light intensity change when the short is removed, the light will dim when the short is disconnected from the circuit as the current will drop.
I see @Tester has given some info while I was posting to this. Since there are a couple of relay circuits involved, as a start, you could at least remove one relay at a time to see which one has the short on it.
Thanks for all the feedback. Order some new relais.
I think all the front lights are working.
For a relay to develop an internal short to ground is not very probable. Whereas damaged wiring is much more likely.
I think Cougar meant to remove a relay and see if the fuse still blows, which would indicate that the wiring controlled by that relay is not at fault. When/if you remove a relay and the fuse does not blow, you know that the short is in the wiring oontrolled by that relay
Many vehicles with a hatch gate have wiring that runs next to one of the hinges. Those wires flex every time the hatch opens, and after a while they tend to break.
What @BillRussell stated about my previous comment is correct. I didn’t mean to say there is a faulty relay causing the problem. Relays are basically remote switches and in this case it is used to apply power to other circuits tied to the switched contact of the relay. One of the two relays most likely supplies power to the circuit that has the problem and by knowing which relay it is it will show you which direction you have to look for the trouble. You are going to need a wiring diagram if you work on this yourself. You can purchase manuals on Ebay. Here is one of them. They are worth their weight in gold in help solving problems like this. They save so much time in hunting things down.
Any chance you have a tow hitch with trailer wiring? This can cause a short in the tail light circuit.
I had to trouble shoot a short on my friend’s car recently and it turned out the short was in one of the lamp sockets. It is a pain to narrow these down and a little bit of luck is also needed.
Concur w/ @wentwest , my first guess is there’s chaffed wire insulation in a wire running to a door or trunk lid. I had a similar problem on my Corolla where the rear license plate is part of the trunk lid, and there’s wiring from the body to the trunk lid to provide the license plate light bulb. That wiring chaffed and eventually broke from repeated opening and closing of the lid. In my case it didn’t cause a short, just the known good license plate bulbs wouldn’t light. But it could have just as easily caused a short and blown a fuse.
All fixed, at least found the problem.
So first, yes I got the maintenance manual and wire diagrams, which showed that rear running lights on fuse #22 also are connected to front running lights, which are the signal lights, or blinker lights.
The blinker/direction lights work left/right, but together with backs as running parking lights do not.
So here is the issue.
I had installed LEDs in all positions, but to avoid hyper flashing I had to use resistors. And after I had installed the ones for the front the fuse blew. So after I removed the resistors the hyper flashing was back the fuse did not blow anymore. So these cables additions caused the short.
So we are back up and running, with hyper flashing, but at least with rear lights now working again.
Thanks all for your support.
Now what I need to try to resolve is finding LED solution for front to avoid hyper flashing, without cause short, while using LEDs, which seems not that easy for this model.
Anyway, all set with this issue.
You could have told us this initially…
series resistors should not have caused this, as they can only decrease current. Are they wired in parallel? What was the value?
If I had that problem I’d just replace the LEDs with conventional bulbs.
https://visual.ly/community/infographic/how/4-ways-get-rid-hyper-flash-led-turn-signal-lights
Check solution 3. You might replace the flasher relay with the referenced thermal relay if one is available.
As Bill writes, that information should have been included in the first post. But it seems that one would have suspected that changing to LED lights on a vehicle that did not have them would have been the big clue.