Heater blower ?/problem

[panhead59]

Working on 68. Heater blowermotor does not work. Replaced motor, resistor and fan speed switch. Fuze and ground are good. I have power to connector that plugs into blower motor. Still doesn't work. What am I missing ? Tks in advance

[pjmoreland]

Do you have a ground wire in place on the motor and does it have a good connection?

[panhead59]

Yes good ground. Shouldn't the motor run with unplugging hot wire and running a wire straight from batt. + to blower motor ? Grounded of course.

[pjmoreland]

Originally Posted by panhead59

Yes good ground. Shouldn't the motor run with unplugging hot wire and running a wire straight from batt. + to blower motor ? Grounded of course.

It definitely should run like that. Try running a wire from the batt - to the blower motor housing as well in a spot where the metal of the housing is exposed through the paint.

I wonder if your fan is jammed somehow inside the housing preventing it from rotating.

[panhead59]

With jumper wire on both pos n neg from battery to motor it still doesn't run. Second "new" motor thinking 1st one could be bad. Both these new motors and the old one do not run when hooked directly to 12v(battery)

[pjmoreland]

See if it will run when removed from the heater housing.

[panhead59]

Nope. Does not work holding in hand hooked up directly to batt

[pjmoreland]

Wow. That's crazy. Is the motor housing made from multiple metal segments? If so, try grounding the individual segments.

[panhead59]

Ok tks. I'll move ground around. At this point I'll try anything !!!!!

[dmjlambert]

I'm thinking the housing mount hole where you attach the ground or neg battery jumper does not have sufficient amount of paint removed to bare metal to make a good ground connection. New blower motor needs some of that paint removed, or perhaps a star washer to really bite through that paint.

[panhead59]

Tks for replies. I thought of that screw that connects to the ground wire. But even grounding motor case, after sanding paint off, directly to battery, and positive connection directly to batt. Motor still doesn't run. I even returned the 1st motor I bought thinking it might have been defective. Any other thoughts ? Anyone?.

[dmjlambert]

Try a different battery and different wires to do your test. At the car parts store explain the problem and hook it up to a battery and confirm it works before buying the next one.

[Stocker]

Dumb question but I gotta ask -- have you verified nominal 12VDC between the two wires with a VOM, or at least a test light?

[panhead59]

Yes. I use test light as the positive wire. It lights up when touched to positive terminal on motor. Going to go out now and isolate battery completely from truck. This shouldn't be "rocket science " but it sure is kicking my @#$ !! Tks again for all replies

[panhead59]

I should mention one " find". I get no power from fuze box to 1st connector ( brown wire) going to on/off switch. If I hook up temporary wire from heater fuze to that connection, I've got power all the way to the blower motor. So most likely a short probably going into fuze box. So I'll isolate truck altogether. New motor was never connected to truck wiring. Just directly from batt to motor. So that short is irrelevant to new motor since it was never hooked up. Make sense?

[panhead59]

Ok. Motor still doesn't run when completely isolated from truck. Hooked up to batt only. Another bad motor ? As dmjlambert suggests I think I'll order another one ( 3rd ) and test at store. What do ya'll think ?

[pjmoreland]

A test light has resistance, so it will prevent the motor from turning if the test light is used as the power lead. You should, however, see the test light lighting up in your scenario which would indicate current is flowing successfully through the motor (a good thing). Try hooking your motor up to the battery with two regular wires. Test wires with alligator clips are very convenient for these types of tests.

https://www.amazon.com/WGGE-WG-026-P...s%2C217&sr=8-3

[pjmoreland]

Check out this video.

https://youtu.be/9t8BkpavIoE?feature=shared

[Stocker]

Originally Posted by panhead59

I get no power from fuze box to 1st connector ( brown wire) going to on/off switch. If I hook up temporary wire from heater fuze to that connection, I've got power all the way to the blower motor.
So most likely a short probably going into fuze box. Make sense?

It sounds to me like you are describing an open circuit, not a short circuit.

If a power wire is shorted (to ground), it will likely blow a fuse -- or make smoke.

Think of an open circuit as a blown fuse -- that is, a gap in the circuit, preventing the flow of electricity.

[panhead59]

Yes stocker u r correct. Sorry for my sloppy and incorrect terminology. Pjmoreland u r also correct. Tks to u both and ALL replies. Motor does run hooked up to battery but not using test light as one of the wires. Tester lights up but doesn't allow motor to run. So what now ? We know motor is good. Old motor was probably good also. So if I go back to original scenario- install motor . Got power to hot wire at motor. So that temporary wire from heater fuze is not the fix. I'm guessing now to be honest. Is there a better unused fuze/circuit that I could use ? Seems like some resistance in heater circuit.

[pjmoreland]

It would be good to do one small step at a time to see where things go wrong.

1) With motor reinstalled, see if it will spin with two wires directly to the battery.

2) See if the motor will also spin using the stock grounding wire and one wire to the positive terminal of the battery.

Once it passes those two tests, then we can dig into the stock wiring to see what's going wrong there.

[panhead59]

Ok tks. I really appreciate the help. I haven't been on here in a couple yrs since I finished "refreshing" truck. Never gives me any issues
Till now. Can't complain !!