Blower motor issues

[inition]

The fuse block behind the passenger seat in my 81 Delorean is a complete rats next . There are several fuse blocks, tons of cut wires and melted plugs. The 20a for the blower motor is in one of these melted plugs. The AC blows cold for a few minutes then the fuse blows and the blower motors shuts off at all fan speed positions. First off, I want to find a way to fix the fuse blowing issue, then restore the wiring. Is the blower motor thermally protected somehow? Would a bad blower motor do this? Why would the previous owner hack up the wiring so much? Is there a updated fuse block available?

[sdg3205]

Your circuit breaker is probably 25 amps and tripping. It's in the relay compartment against the wall, not part of the fuse block. It should be 30 amps.

[kings1527]

Like Dave said.

When the blower starts to be on its way out (as was mine, too), it starts to draw more amperage which causes the breaker to trip. I installed a 30a breaker from Auto Zone for about $2.50 or so and the problem was solved. But I'm guessing it'll be relatively soon when the blower itself will go out. By design, it's not supposed to trip the 25a breaker.

I detailed installing the new breaker on my blog located here:
http://delorean6575revisited.blogspot.com/2013/08/resurrecting-r12-ac-system-and.html

It's toward the end of the post.

[sdg3205]

Here's more information:

http://dmctalk.org/showthread.php?t=9475

Tis the season for blower motor issues!

[Jonathan]

http://dmctalk.org/showthread.php?40-All-Wiring-Schematics&p=7640&viewfull=1#post7640

Have a look through the fuse and relay area schematic in this post as well as the other individual diagrams in this thread. If you haven't seen them before and aren't sure what that area should look like, the diagrams could help.

[Ron]

^+1^


The fuse block behind the passenger seat in my 81 Delorean is a complete rats next . There are several fuse blocks, tons of cut wires and melted plugs. The 20a for the blower motor is in one of these melted plugs. The AC blows cold for a few minutes then the fuse blows and the blower motors shuts off at all fan speed positions. First off, I want to find a way to fix the fuse blowing issue, then restore the wiring. Is the blower motor thermally protected somehow? Would a bad blower motor do this? Why would the previous owner hack up the wiring so much? Is there a updated fuse block available?
$.02

Since you want to get the fan going first, I would splice in a good fuse holder for fuse #10. Then suspect an overload due to wiring other components on the fan circuit or the blower motor itself.
It probably has nothing to do with the breaker because a fuse blows much sooner/faster (especially when is of a lower rate ;-), and, the breaker is not used except for High and Max speeds while you loose ALL speeds...

I would first check the motor's amp draw. Common meters will not handle measuring the fan's amp draw, but you can rig a jumper wire with a fuse holder and start with a high rate and work down and see what size it blows at to get an idea, Either way:
Turn Key to OFF. Disconnect the motor feed and test connected to the battery (+) and the motor.
If ok, check for incorrectly added loads due to miswiring (the door lock telltail should be the only other load. it's tiny), etc. by: plugging the motor back up, pulling fuse #10, and measure connected to the battery and the load side of fuse #10. (Repeat this step with Key ON for GP).

Measuring the resistance from the motor to ground would be a good thing to do for GP (...bad grounds other connections can magically ignore theory ;-)

[inition]

Good information everyone, thanks so much. I'm going to do some tests this weekend.