Heater fuse problem

[cam.man67]

So here's the problem: Last week the heater switch in my truck went bad. All right, no problem, got it ordered from ECE, delivered today. I put the thing in, got a new fuse (in my haste to take the old one out I blew a fuse when the hot wire connected with the dash) everything works fine. For about a minute. Then the fuse blows again. I know the PO rewired the cig lighter so it pulled off the heater fuse, so I unplug my GPS unit, put another fuse in, and the heater works fine. And then it blows again.

Long story short, I don't know what to think. According to the fuse box, that should be a 10 amp fuse, which is what I put in. I haven't changed the wiring in any way, so I can't figure out what could have possibly changed. Suggestions?

I'm tempted at this point to put a 25 amp fuse in and be done with it. Any reason I shouldn't do that?


Thanks in advance!

[butters_72]

well if you put in a fuse bigger than whats called for you risk melting the wires or causing more damage than good, those switches run a relay and your relay could be shorting out, have you checked that? if you do decide to put in a bigger fuse i wouldnt just jump to a 25 right away, you could try a 15 amp safley to see what happeneds

[cam.man67]

Ok, so this relay is inside the switch? It doesn't appear to readily come apart.

[hugger6933]

What speed is the fuse blowing? Is it on high or any position from low on up? There is a high speed relay that is on the heater box behind the glove box. Have you tried to run a jumper [fused of course] to the fan motor? When I first started to try my fan on my 68, I didn't have anything. I started out with a jumper to the fan motor it sparked then ran fine kinda like it might have been stuckor something. after that it all worked fine for a little while then the swicth stopped. I took it apart and cleaned the contacts all is well now. Jim

[cam.man67]

It's high speed. I took the panel off again this morning and found a short in the high speed wire. Cut off the bad spot, it's good to go. Thanks for the suggestions, everybody!

[kwmech]

Change the blower motor itself. It's drawing too much current

[Wrenchbender Ret]

Put a 20 amp. fuse in it. The fuse is going to blow long before any wires get hot. It probably has a replacement motor that pulls more curent then the original.