Heater motor fuse popping

[cppursell]

Hi all! My '67 C10 is still on the road, and hauls my '62 Airstream Overlander (I live in it full time). As you know, it's often a joy but sometimes frustrating to keep everything working, and this time I'm stumped... may I get your insight?

Heater fan motor keeps popping it's 10a fuse. ...I've already replaced the motor, switch, speed resistor. I actually bypassed the fuse panel and am using an inline 10a ATO fuse. I inspected the original heater harness and it's in good shape. The connection between the fuse and harness connector is good, multi-meter doesn't seem to show resistance. Motor is grounded well.

Symptoms: When I replace a fuse, the motor runs at all speeds when the engine is stopped. When I start the truck, the fuse pops when fan is at high speed, sometimes lower.

I'm defeated, do you have any ideas? Only thing I can think of is a failing voltage regulator, since I notice, momentarily on occasion, the power fluctuates and the engine sputters at idle?

Thanks for your help!

[cppursell]

I'll add that even a 25a fuse pops...

[pjmoreland]

Here's someone who had the same problem and fixed it by cleaning up the ground connection.

http://67-72chevytrucks.com/vboard/s...d.php?t=727010

[Wrenchbender Ret]

You shot down my first thought with your second post. 10 amp fuse is not enough for a blower motor.
Put a volt meter on the battery & see what the charging voltage is. It should be around 14 volts. No more then 14.5 & steady with the engine about 1500 rpm or higher.

George

[cppursell]

Thanks I'll try that again, though I scraped the ground before and secured it tightly!

Originally Posted by pjmoreland

Here's someone who had the same problem and fixed it by cleaning up the ground connection.

http://67-72chevytrucks.com/vboard/s...d.php?t=727010

[cppursell]

Yes I'll do those tests, thank you again! I looked it up and 10a is correct for the blower motor, and I wouldn't want to risk overheating wiring. I hope I can nail this down, fingers crossed.

Originally Posted by Wrenchbender Ret

You shot down my first thought with your second post. 10 amp fuse is not enough for a blower motor.
Put a volt meter on the battery & see what the charging voltage is. It should be around 14 volts. No more then 14.5 & steady with the engine about 1500 rpm or higher.

George