blower motor question
Thread Starter
Pro
Joined: Jun 2002
Posts: 503
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From: straight flossin' since 2002
blower motor question
I have a friend who owns a '73 Stingray. He just replaced what he refers to as a "blower motor". He says it has three speeds, but whichever speed he turns it to seems to run too slow and doesn't blow strong enough. I told him I'd go onto the Forum and see if I could get some answers for him. Thanks for any help you guys can give me. :)
Safety Car
Joined: Jul 2002
Posts: 4,269
Likes: 3
From: St. Charles IL
Cruise-In 5-6-7-8-9-11-12 Veteran
A CI-6 Car Show Winner
Re: blower motor question (true2myself02)
There are some resistors mounted to a plate in the air stream of the heater box. The resistor assembly is accessed from the engine compartment. The resistors are what provides for low and medium speed operation. If the resistors are burned up that could cause part of the problem, but high speed bypasses the resistors, so the problem could be broken wires between the speed selector switch and the blower, or a bad speed selector switch. Suggest checking all the above for resistance and continuity before ordering a bunch of parts. Get a schematic for the wiring if you don't have one already, it will identify the wires by color and tracer colors. Good luck, wiring issues on these cars can be a lot of frustration, but at least the wiring in question for this problem involves only a small wiring harness that is routed from the shifter console directly to the blower motor. :cheers:
[Modified by Big Fish, 9:43 AM 6/10/2003]
[Modified by Big Fish, 9:43 AM 6/10/2003]
Burning Brakes
Joined: Jun 2002
Posts: 792
Likes: 2
From: Norcross GA
Re: blower motor question (Big Fish)
Is he getting three speeds? These blower motors are notorious for not moving any significant volume of air at any of the three speeds. There is information out there on how to replace it with a stronger motor.
[Modified by Bobchad, 2:48 PM 6/10/2003]
[Modified by Bobchad, 2:48 PM 6/10/2003]
Thread Starter
Pro
Joined: Jun 2002
Posts: 503
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From: straight flossin' since 2002
Re: blower motor question (Bobchad)
Thanks for the response! I told my friend Felix what you said. Now he wants to know where he would get the info to replace the AC blower motor with a stronger one. Thanks for any help you can give! :thumbs:
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
Re: blower motor question (true2myself02)
Before going to the effort to upgrade the blower motor, try the following:
1. check the grond on the motor. A bad ground will significantly slow down the motor.
2. Remove all leaves, debris, crud from the evap box. You'd be amazed at how much stuff falls into the intake over the years. If the evap box is clogged up, even a better motor won't help. On my 71, Itg was possible to snake a small (1.5" diam) flex hose down from the cowl to vacuum this stuff out. But the best way is to open the evap box from the engine side and get it all out.
3. Change the fan to a late C3 fan. The blade shape and depth changed to deal with a larger cabin and more glass when the shovel back changed to the fast back.
If you do all these and nothing helps, go to the archives and see what's involved in installing a C4 fan. Hint: It aint easy......
1. check the grond on the motor. A bad ground will significantly slow down the motor.
2. Remove all leaves, debris, crud from the evap box. You'd be amazed at how much stuff falls into the intake over the years. If the evap box is clogged up, even a better motor won't help. On my 71, Itg was possible to snake a small (1.5" diam) flex hose down from the cowl to vacuum this stuff out. But the best way is to open the evap box from the engine side and get it all out.
3. Change the fan to a late C3 fan. The blade shape and depth changed to deal with a larger cabin and more glass when the shovel back changed to the fast back.
If you do all these and nothing helps, go to the archives and see what's involved in installing a C4 fan. Hint: It aint easy......
Burning Brakes
Joined: Jun 2002
Posts: 792
Likes: 2
From: Norcross GA
Re: blower motor question (true2myself02)
http://home.attbi.com/~jchadwick/ventilation.htm Click on upgrading the fan.
Intermediate
Joined: Jan 2003
Posts: 29
Likes: 0
From: Lake Orion MI
Re: blower motor question (Bobchad)
Bobchad's web page has pretty much everything you need to know. One more thing to consider... A common cause of "No High Speed" on a Blower Motor a blown fuse in the in-line fuse holder. This is located under the left fender outboard of the brake master cylinder and next to the washer bottle (at least on my 1974 Coupe). It should have a heavy red wire with a twist apart fuse holder.
On "High Speed" the current feed is direct to the blower motor and by-passes the resistor.
On "High Speed" the current feed is direct to the blower motor and by-passes the resistor.
Melting Slicks
Joined: Sep 2001
Posts: 2,218
Likes: 0
From: Glendale AZ
Re: blower motor question (Bobchad)
http://home.attbi.com/~jchadwick/ventilation.htm Click on upgrading the fan.
cheers
chad
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Burning Brakes
Joined: Jun 2002
Posts: 792
Likes: 2
From: Norcross GA
Re: blower motor question (71'AirStrike)
My pleasure. Let me know if something doesn't seem right or if you have something to add and I'll make sure you get credit.
FYI. ATTBI is becoming Comcast so I don't know if it will be at the same address after 7/1. Check my profile as I'll update my web address if it changes.
FYI. ATTBI is becoming Comcast so I don't know if it will be at the same address after 7/1. Check my profile as I'll update my web address if it changes.
