Blower Motor Inop on High Speed

[TurboWh1]

Hey guys, looking for some advice here. 87GN, The blower motor isn’t working on the high speed. I’ve swapped the resistor and relay on the top cover of the engine side of the heater box — no change. I’m thinking the blower motor must get power from a different source than when the fan switch is in the 1,2 or 3 settings...? I also swapped the heater control unit inside the vehicle just to see if that had an impact. No change there either.

I did a voltage test on the purple wire that supplies power to the blower motor. When the fan switch is on 1,2 or 3 settings the voltage is the same, around 11.2 volts. When switch is moved to high speed, voltage drops to 6 volts and blower motor not working.

 

[salvageV6]

https://turbobuick.com/threads/blower-motor-info.190689/#post-1340570

 

[salvageV6]

Follow the fat red wire out of the silver high speed relay over to the pass. fender well area and find this connector and wiggle it, high speed will probably work again.

High speed is operated through the relay with power from a fusible link always hot wire.

 

[TurboBuRick]

X2 ^^^^

 

[captndave737]

I had the same problem and chased it for a while. I was getting voltage to pin E of the relay but the relay wasn't closing. It ended up being corrosion resulting in a bad connection at C93. Just because there's voltage doesn't mean the wiring is capable of carrying the current needed.

 

[TurboWh1]

Thanks for the info guys, I did check the connector at antenna area and it had power at the red wire. I didnt pull it apart though, i just slid the probe of my multi meter in to check it. I'll check the red wire at the relay to ensure voltage is getting there and pull the connector appart and inspect the terminals as well. Sounds like they may be corroded....

 

[GNRick]

My high speed blows, but not very well. Actually all 4 speeds are pretty lame. Replaced blower motor with an a.c. Delco from Rock Auto. no change. Any tips? Sorry to hijack.

 

[captndave737]

The connector where I had a problem was C493 which is in back of the radio. I was able to get to it by lowering the glove box. You might have to pull the radio. Easy to do. Pull off the the bezel and there are 4 7mm screws holding the radio in. Antenna connection is on the side, a ground connector on the back right side of the radio body and a few plugs in the back and the radio slides out.

The high speed side gets its power from a useable link through the NO contacts on the relay. The other speeds get power from the blower switch through the NC contacts on the relay so the relay can be dead and you'll still have the lower speeds.

 

[captndave737]

My high speed blows, but not very well. Actually all 4 speeds are pretty lame. Replaced blower motor with an a.c. Delco from Rock Auto. no change. Any tips? Sorry to hijack.

Thats a tough one. Maybe the contacts in the relay have burned and have high resistance. Try pulling the relay and jumping Pins A & D in the connector. If the fan runs well on high I'd replace the relay.

 

[GNRick]

Will try it. Thanks Captain!

 

[GNRick]

Which is A and which is D?
https://www.rockauto.com/en/catalog...trical-switch+&+relay,blower+motor+relay,3088

 

[Chuck Leeper]

Actually all 4 speeds are pretty lame.

Ground?
Motor worn out?

 

[captndave737]

A has a purple wire that goes to the blower motor, D has a red wire that's a fuseable link. I'd look but my car is at RC's for body work and paint for the next few months.

 

[captndave737]

Ground?
Motor worn out?

Ground very likely. He recently replaced the motor.

 

[GNRick]

I ran a hot wire direct from battery to the fan. No improvement. One thing I noticed is that more air seems to blow from the "vent" position as I slide the temperature control to cold (i.e. sliding it to the left). Could that valve with the vacuum line on the bottom in line with the heater core need to be replaced?

 

[TurboBuRick]

I ran a hot wire direct from battery to the fan. No improvement. One thing I noticed is that more air seems to blow from the "vent" position as I slide the temperature control to cold (i.e. sliding it to the left). Could that valve with the vacuum line on the bottom in line with the heater core need to be replaced?

Could be. You can test it with a vacuum pump.

I would take a look at the vacuum selector on the back of hvac control. They fall apart.

 

[Chuck Leeper]

I ran a hot wire direct from battery to the fan

Did you do the ground side, too?

 

[TurboWh1]

I had the same problem and chased it for a while. I was getting voltage to pin E of the relay but the relay wasn't closing. It ended up being corrosion resulting in a bad connection at C93. Just because there's voltage doesn't mean the wiring is capable of carrying the current needed.

Thanks all!!Problem solved

 

[Boostrules]

Thanks all!!Problem solved

So was it corrosion, wiring, or the relay?

 

[GNRick]

Did you do the ground side, too?

Yes. Made no difference. Replaced the relay today because the new one is nice and shiny. So the air blows stronger with slider on the cold side. Didn't check for anything broken in the slider controls. Thinking maybe this is normal?