I'm blowing heater fuses and I'm sure it's a short because the fuse blows immediately. I've been trying to find the ground wire from the blower towards the switch. The two wires from the blower I've followed to the three wire connector. From there it just disappears. It goes into the wire loom, but I can't find where it comes out. I know its not connected to the block, but could it be connected somewhere else? I'm not even real sure that's my problem.

I checked voltage from the ground wire in the relay to the red wire in the relay. Show 12.7 volts with engine off. Tapped power and ground from the relay to the blower and it works. Does this mean the ground is good?

When I put a new fuse in, even with the heater turned off, it blows immediately. I've been using 25 amp fuses. I tried a 30 amp and it lasted microseconds longer but still blew.

Please, this is driving me nuts. Any help??

 

i wouldn't use i bigger fuse that can cause you more problems.

sound like a dead short. check all your power wire for a scuff or cut that could be grounding.

you say it blows with key off? sould only have power to blower if key on and blower switched on. you may have a bad relay shorted there. do you have 12 v on ground at the relay?

 

Do yourself a favor and get a Haynes repair manual for the your car. They are a life saver since they contain most all the wire diagrams for everthing in the car. They will have trouble shooting guides and if all else fails, get the Haynes electrical manual. Both of these have gottem me out of trouble many times. Good luck.
cc 82Z-28

 

The fuses only blow when I turn the key on. I have the Haynes manual and it only show there is a ground, but not where it is.

My idea is this, please tell me if you think it will work: Splice into the black wires and ground them on the block. Will this screw up anything down line from the splice?

 

Go and check on the electrical manual that Haynes sells for trouble shooting problems with all types of electrical systems on a car or truck. It is a pretty good manual and it fills the void that is left from the car manual. It will show you how to trouble shoot heater blowers, starters, charging systems, etc. I don't think what you want to do is a good idea, sounds like you've got a dead short. Maybe the heater motor has gone bad or the switch itself. I'm not much help at this point, I'll go and get my manual and see if it gives me any ideas for you.
cc 82Z-28

 

I think I figured out where my problem is. When I first put the motor in, the battery cable was melted by the open headers. I think maybe the power wire to the heater was also melted, but not as bad. I didn't check it and just put it in the metal heat shield. Tomorrow I'll pull it out and check it real good. If that's not the problem, I've got quite a job ahead. I picked up the Hyanes electrical manual today, and unfortunately, they say to do everything I've already done. I hate the thought of tracing everyone one of those wires. What a PITA!