Blower motor problems

[Paulonline3d]

My Delorean is working after a lot of reading and repairing from the forum. However, my AC blower fan is acting up, and can't find any similar issues from other threads.

I have the blower motor out so that I can see its operation, and it seems to be underpowered. On fan speed 1, no operation, motor doesn't turn. Fan speed 2 looks like motor is barely trying to turn. Fan speed 3, motor spins, but looks slow. Fan speed 4, motor spins for 5 seconds, and then circuit breaker pops, shuts off, then on, then off...

I have already replaced the resistor pack. I did swap in a replacement blower motor, which did the same thing, so not the motor itself. I put a voltmeter on the motor while attached, and readings seem very low. On fan speed 4, voltage was about 5V (thought it should be 12V).

Any ideas on what is causing the underpowering of the fan? Would like to have AC working again, now that I've gotten it drivable. Thanks for your help.

- Paul

[David T]

Check the ground wire, make sure it has good connectivity to ground for the motor.

[Paulonline3d]

Check the ground wire, make sure it has good connectivity to ground for the motor.

I used my jumper cables to connect a good ground from the engine bay to the screw on the blower motor that has the ground connection. It may have made things worse, but still similar. Also sanded off the paint where the screw connects to make sure is was connecting to bare metal. Same.

[TTait]

Use good jumper wires to test either one or both of your blower motors directly to the battery. Best practice would suggest that the positive wire would be fused. See if the blower motor operates properly when the wiring is perfect just to ensure your blower(s) are in fact good.

[Elvis]

The Circuit Breaker pops ?
Then meaure there the voltage and replace the 40 year old $5 part if needed.

[Paulonline3d]

Use good jumper wires to test either one or both of your blower motors directly to the battery. Best practice would suggest that the positive wire would be fused. See if the blower motor operates properly when the wiring is perfect just to ensure your blower(s) are in fact good.

Connected blower motor directly to battery (briefly), and it spins up like a champ! But connected in place, behaves anemic.

Got a 30A circuit breaker, and hot wired it in place of the old 25A (different connectors, so required some creativity). Same action on speeds 1-3, and now 4 does not work at all. Will take another look to make sure I put circuit breaker in properly.

No joy! Thanks for your continued help.

- Paul

[Bitsyncmaster]

Connected blower motor directly to battery (briefly), and it spins up like a champ! But connected in place, behaves anemic.

Got a 30A circuit breaker, and hot wired it in place of the old 25A (different connectors, so required some creativity). Same action on speeds 1-3, and now 4 does not work at all. Will take another look to make sure I put circuit breaker in properly.

No joy! Thanks for your continued help.

- Paul

Speeds 3 and 4 run though two relays used to reduce current through the fan switch. Speed 4 runs power directly to the blower (no resistor).

[Paulonline3d]

Speeds 3 and 4 run though two relays used to reduce current through the fan switch. Speed 4 runs power directly to the blower (no resistor).

So on speed 4, should I be seeing 12V at the blower motor? Mine seems to have only like 5V on speed 4, and all the speeds look under powered. Wondering what would cause a low voltage going to the blower motor on all speeds. Thanks.

- Paul

[Bitsyncmaster]

So on speed 4, should I be seeing 12V at the blower motor? Mine seems to have only like 5V on speed 4, and all the speeds look under powered. Wondering what would cause a low voltage going to the blower motor on all speeds. Thanks.

- Paul

You should see close to battery voltage. If your only seeing 5 volts than your circuit breaker of a bad connection is probably dropping the voltage. What does your dash voltage gauge read with the headlights on (for a load).

[Paulonline3d]

You should see close to battery voltage. If your only seeing 5 volts than your circuit breaker of a bad connection is probably dropping the voltage. What does your dash voltage gauge read with the headlights on (for a load).

Didn't get to check that yet, but I did check the battery voltage by itself with a voltmeter, and it was 11.97V.

- Paul