Black89

Here's the story, my son called called me last night from Florida where he's stationed in the Coast Guard. He's having some issues with the turn signals blowing the fuse the minute he turns the key on. He said all the bulbs are good and working when he uses the hazzards. So while trying to diagnose this over the phone I told him he's obviously got a dead short someplace. There is no trailer hitch or harness on the Jeep so nothing to check there. Rest of the rig is bone stock. I told him to check the harnesses under the hood for any breaks at this point but it has me wondering if the wire harness in the column has a break in it? It's got the old GM column in it and I have seen some in the past where the tilt on the column gets used so much that the harness from the turn signal switch actually breaks but the harness does run in a plastic sleeve which would make contact for a dead short pretty tough. I guess I need to know if anyone else has run into this where the turn signal fuse blows when the key gets turned on? He's on Duty all day today so I want to see what we can figure out before he calls me Sunday and I leave for Montana for the week Monday.

Thanks guys,

F1Addict

Pulling the flasher relay would be the first diagnostic tool. That would at least tell you what side of the circuit is causing the short. The order of flow goes...

Battery>fuse>flasher relay>multi-function switch>bulbs.

Unfortunately, there isn't any one cause so there has to be some investigation.

Black89

Sorry I forgot to mention that he said the flasher was clicking off with the the turn signals off when it was keyed up. He put a new flasher in then it blew the fuse. I told him to put the column tilt straight then try a new fuse and see it may be a wire in the column. I'm thinking it's either a bad switch or a bad harness in the column at this point.

thanks,

F1Addict

The flasher relay is load-sensitive so it oscillates when it senses a load. That load normally comes from the bulbs but it sounds like it may be coming from elsewhere, now. A new multi-function switch comes with the harness that connects under the knee bolster below the column. He could try disconnecting that connector and testing again. I suspect that will stop the fuse blowing and further narrow down the source.

This is what the multi-function switch connector looks like...


If he's got an airbag, I can't offer advice beyond that connector because I know nothing about that column hub or how to access the multi-function switch on an airbag equipped XJ.

disguay

I saw something similar to what you were describing on an 89 honda. Turned out the wires in the socket for the turn signal bulb had shorted and I had to wire in a new socket. Something super simple, but I kept overlooking it and it caused all sorts of weird issues.