Author Topic: Blower Motor will not adjust speed (Read 5500 times)

stingray · « **on:** August 07, 2006, 01:23:11 PM »

Hello I am a new user, I have a 78 T/A with 30k miles, Last night I have a local installer ( Curcit City) install a radio & now my Heater blower will not change speeds. It is constently running but a very low speed. I have cheeked all connections but on the controller & cannot find the ground on this controller.

Please help!
Regards
Brett

ta78w72 · « **Reply #1 on:** August 07, 2006, 01:40:15 PM »

Check to see if your A/C clutch engages. If not, you have a faulty A/C control or wire to blower switch.

DId they cut into your harness? Or did they pull power directly from the battery? That's a tight space back there, you'd better check your A/C ducts to make sure they didn't break them out. Did they cut out your dash?

If you don't have A/C, then you have a switch or wiring problem.

Make sure your connectors are installed at the high blower relay and the resistor.

stingray · « **Reply #2 on:** August 07, 2006, 05:05:05 PM »

The AC compressor did not work prior to the installation, The fan is running at the normal low speed but the swtich does not make the speed increase. I am not sure how they applied power. They did cut out my dash for fitting. They verified all connectors are plugged in. What about the grounding of the switch I could not see how that is accomplished.

Brett

ta78w72 · « **Reply #3 on:** August 07, 2006, 06:12:23 PM »

The blower motor grounds on the A/C bracket. I doubt you've got a grounding issue because the motor runs.

What position do you have the A/C contorl mode at? It's the top lever that slides horizontally. If at the OFF position, you only get a low speed on the blower motor regardless of the switch setting. Try putting the A/C control mode on VENT and then move the switch to high.

Maryland Bandit · « **Reply #4 on:** August 07, 2006, 10:03:48 PM »

Possible chance they knocked the fan switch connector off the panel during the install. It's meant to run on low/off to keep fresh air flowing through the car.

Eagle 1 · « **Reply #5 on:** August 07, 2006, 10:14:56 PM »

When mine done this, it was the ac control switch located next to the vacumn switch.

fb_rider · « **Reply #6 on:** August 07, 2006, 11:09:22 PM »

I had the same problem also - it turned out to be a connector that wasn't connected to the heater control unit (I think it was on top if I remember right). It almost doesn't even look like a regular connector. I think you can get to it by removing your oil pressure and fuel guage. I hope this helps.

stingray · « **Reply #7 on:** August 08, 2006, 08:00:29 AM »

Thanks for the info you guys are great! I will tear into it this weekend. Eagle 1 "Where is the AC control switch & how can I check it? Do you think it is the switch itself?

Brett

fb_rider · « **Reply #8 on:** August 08, 2006, 08:40:21 AM »

I'm talking about the control unit that is in the dash, where you turn on your heat, a/c, adjust the temperature, blower, etc. If I remember correctly, you can remove the dash bezel and the guages above the control to see the top of the unit. There was a wiring harness that attaches to the top that was left off on mine. The low speed blower always works no matter what, but without that harness attached no other speeds will work. Hope this helps.

Eagle 1 · « **Reply #9 on:** August 08, 2006, 09:57:17 PM »

Its behind the ac control unit, mounted on top. Should be a brown rotating switch.
Like mentioned before, remove your dash bezel and remove the ac control unit. You wont be able to get it all the way out, unless you unhook the temp control cable. However thats not necessary, as you should be able to access the switch.
My switch was broken, which looking the way its made, that could be common.