honobiahunter

I have a '91 W250 5 speed that keeps blowing the dash/taillight fuse. I've searched and searched the threads and many have had this problem but none have ever followed up with what the issue was that kept popping the fuse. Was hoping someone could chime in with the possible cause for it. I'm hoping it's something that's been a common problem that someone has already figured out. I'm banking on it being a bad headlight switch or bare wire. Any help is appreciated.

thrashingcows

I'm betting on the grounds, Redo all your grounds. Remove, sandpaper clean all connections, and re-install.

j_martin

I disagree with TC. Open grounds won't blow fuses. Look for a bad bulb socket or pinched wire. I've found a few pinched by the spare tire.

thrashingcows

OK fair enough...but still good advice right....

2mtrucks

Check your trailer wiring harness and plug...just got a 1991 with dead short in the dash light/running light/tail light circuit...turned out to be a bent copper spade in the trailer harness plug that made contact with the metal plug body and immediately blew the fuse as soon as you pulled the light switch out....I have owned several trucks that were fire hazards when I got them due to inept trailer or auxiliary wiring.

honobiahunter

Thanks guys. I'll check all 3. I did notice that the front passenger side fender marker bulb was blown and totally black. The bulb also fits loose and works intermittently in this socket. I pulled the old bulb out and left it out. I then put in a new dash light fuse and it still blew. Can a bad lamp socket still short the system even without a bulb in it? BTW, the trailer wiring is hacked up so that might be the problem if it's not the socket.

dan123dbl

If you've done recent work to your truck check in that area. I repaired a fuel tank on a different vehicle and ended up pinching a wire between a washer when I was tightening everything down on the frame. Took me a bit of thinking to realize the problem

2mtrucks

I think you are looking for a pinched or chafed wire somewhere...where to look kind of depends on the condition of your trucks wiring. I would look at the most obvious locations...the harnesses to the lights in the front and back...the license plate light wires, and certainly any trailer wiring. A dead short like this is generally caused by a wire making direct contact to a ground. I thinks its unlikely to be in the cab unless you see evidence of a hack electrician.. like improperly installed lights, gauges or other add-ons.

Montana2x2

These harnesses have a lot of sub harnesses that you can unplug to pinpoint the problem area. I'd start at the trailer wiring because most of the time it is not done very good then I'd disconnect both of the tail light harnesses, if the fuse still bows then move to the front of the truck and do the same. Once you get the fuse to stop blowing then you can take a closer look the the sub harness that is causing the problem. If all else fails jump across the fuse with a 10 gauge wire and look for smoke.......Just kidding.

j_martin

Nobody seems to have answered the question. It is yes.

I'd be looking at the hack wiring with a jaundiced eye.

patdaly

I would be focused on the hacked wiring like an Ethiopian on a T-Bone..........

honobiahunter

Y'all are cracking me up. Thanks for all the helpful replies. I'll start with the trailer wiring and if that's not it I'll start isolating different areas by unplugging the sub harnesses. If all else fails I may resort to a 10 gauge jumper wire across the fuse and then walk quickly away when it starts to smoke. LOL

honobiahunter

now my radio has went dead. I checked the fuse for it and it's still good. I'm wondering if this problem is related to my dash light fuse continually blowing.

j_martin

It's a first gen CTD Dodge.

...million mile motor
...150,000 mile body
....35,000 mile electrical system.

Maybe the radio itself died. You need to probe connections to know what's up.

u2slow

^
Prime suspect. Mine was blowing because I had some extra trailer wiring (camper actually) getting pinched/worn by my toolbox. I'd hit bump in the road and lights out.