suggestions - electrical short/problem on feed to blower motor

[OB_WAN]

any help / suggestions would be appreciated.

Here's the situation. The power feed input to the blower motor(a/c heater) fuse connection is melting my fuse panel. this first happened when I got the truck. result was that the fuse was arc'd/melted at the terminal and pushed away from the connection enough to stop the motor from working(did not blow the fuse).

I forced another fuse in there and it worked for a few more months. Well it just happened again. no more forcing fuses in to the socket. fuse socket 9 is no longer able to accept fuses which is not really a problem and I never should have forced the first one in there. Restate: this problem is not a short @ the blower motor but rather prior to the fuse panel or w/in the fuse panel. I'm making this assumption because I'm not blowing fuses.

I'd appreciate any pictures of the back side of a fuse panel if you know of any. something that would show how fuse 9 is connected to the Grey/Yellow wire that is feeding in to fuse 5. for some reason I'm not experiencing any problems with fuse 5(turn lamps, etc). Only fuse 9 so far.

last alternative is cutting the G/Y wire(input), cutting the BR/W wire(output to blower motor), cutting the R/O wire(turn lamps) and just putting inline fuses in but I would really prefer not hacking the fuse panel apart. If there's another unused input wire that can feed 30amps at the run position, maybe I can just move fuse 9 Br/W terminal over there instead(what tool to use?)? I did see a few "unused" parts of the terminal.


On a side note, it seemed like the melting was only occurring when the blower motor was on full. perhaps too much amp draw for the connection between the G/Y wire(at fuse 5) and fuse 9? the fuse never blew and after the first melt-down I replaced the 30amp fuse with a 25amp fuse.

Thanks

 

[franklin2]

Sounds like there is a loose/poor connection in the fuse panel. Just like a loose battery cable can start smoking when the starter is turning, a poor connection anywhere else can also cause heat.

Your best easiest solution would be to go to the junkyard and get another fuse box if you do not want to add inline fuses like you described. These trucks are not that uncommon yet in the junkyards(at least not in my area) and that solution would make the most sense. Also make sure there is no water damage around that area that could have caused the problem in the first place, such as a windshield leak.

 

[Goofyexponent]

What size fuses are you putting in there? They aren't too big for the circuit? I've done this a couple of times.

 

[jcarr]

i've experenced a simular prob on my jeep xj. problem solved with the replacement of the blower motor. as it turned out the blower motor had high resistance and was drawing to much current but not enough to blow the fuse. it even melted the hvac controls in the dash where the fan speed control is.

 

[towcat]

i've experenced a simular prob on my jeep xj. problem solved with the replacement of the blower motor. as it turned out the blower motor had high resistance and was drawing to much current but not enough to blow the fuse. it even melted the hvac controls in the dash where the fan speed control is.

+1 on changing out the blower motor.
also, fix all the components damaged from excessive heat.

 

[OB_WAN]

thanks to all. I wasn't aware that the circuit could cause that much heat w/out blowing the fuse.

 

[SparkandFire]

i've experenced a simular prob on my jeep xj. problem solved with the replacement of the blower motor. as it turned out the blower motor had high resistance and was drawing to much current but not enough to blow the fuse. it even melted the hvac controls in the dash where the fan speed control is.

X2

Dragging blower motor bearings can also cause the wiring to heat up...

DC motors pull current linearly to load... Higher load = Higher current

Might be just below the tripping point of the fuse.