Fan Blower Speed - only High Works
#1
Fan Blower Speed - only High Works
On my 1982, only the High setting on the fan blower works.
So far I have replaced the blower switch, AC High Blower Motor Cutout Relay and the AC Blower Motor Resistor and none of these have fixed the problem.
(I turned the key to Accessories - does the car have to be running to properly test these parts?)
Any ideas?
Thanks!
So far I have replaced the blower switch, AC High Blower Motor Cutout Relay and the AC Blower Motor Resistor and none of these have fixed the problem.
(I turned the key to Accessories - does the car have to be running to properly test these parts?)
Any ideas?
Thanks!
Last edited by ffarina; 09-05-2010 at 01:47 PM.
#4
Racer
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Check ground(black wire)to blower.........sometimes the wire heats and breaks somewhere along it's length.
Try grounding blower with another source ,if it cures your problem, your ground is bad.
Good Luck
Try grounding blower with another source ,if it cures your problem, your ground is bad.
Good Luck
#5
Melting Slicks
i would check for voltage at c137 , drk. blue wire coming out of resistors. since its the common supply to the motor from the resistors. should be able to check it at the high speed blower relay. may be a bad connector or wire. since the low, med, med hi dont work.
believe the key should be turned forward to the on position for fan to work
believe the key should be turned forward to the on position for fan to work
Last edited by speedreed8; 09-06-2010 at 01:54 PM.
#8
Acct suspended by request 19 April 2011
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I just went through all of this. Replaced bad motor. Long story. The fuse is in the fuse box under drivers dash. Depending which year. I have 78 and top right I believe is heat and ac. 25 amp fuse. The high speed works seperate from the fuse/
#9
Race Director
i would check for voltage at c137 , drk. blue wire coming out of resistors. since its the common supply to the motor from the resistors. should be able to check it at the high speed blower relay. may be a bad connector or wire. since the low, med, med hi dont work.
believe the key should be turned forward to the on position for fan to work
believe the key should be turned forward to the on position for fan to work
You've thrown all the parts you can throw at it,its time to get your test light out and actually diagnose the problem.
#10
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Also I found my duct on passenger side kicked in toward firewall and loose. Aparently it was hanging my fan up. Not allowing it to run only but high speed. When I pit the duct in place the fan worked fine. Lot of varables
#12
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No the fuse was good. I had a hard time finding the right size blower wheel for 1. 2nd the Blower duct under the glove box on passenger side was pushe loose into the fire wall. It was keeping the fan from turning. The lower speeds don't put out much voltage. That's why the guys were asking and trying to help in that direction. But check the fuse and duct under dash (glove box). Make sure it is tight to the vent there. Not up against the wheel. If the duct is resting on or blocking the wheel it won't turm axcept on high. Hope you find it. I did the same thing. Replaced relay and blower resistor.
#13
have you replaced/checked the function switch it powers the low speed switch, they are kind of junk especialy the aftermarket ones
Last edited by thiatt; 09-07-2010 at 08:06 PM. Reason: mispoke
#14
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Don't know if this will help you but I did a simplified version of that schematic.
1st.. I would verify the fuse is good.... then i would verify the fuse is making good contact in the fuse panel. Make sure the terminals are not corroded and that the fuse is making good contact.
2nd I'd put the blower motor in a lower speed.. then I would check the purple wire for power... If the purple wire has power then verify the motor ground.
If the purple wire is without power... then go to the dark blue wire and see if you have power.. The inputs to the resistor are Tan, Light Blue and Brown... so when you put the blower switch in the dash in one of the lower speeds it changes which wire gets the power.. the power then runs through the resistor and comes out on the blue wire. Knowing this.. I'd test for power on each of the three wires.. depending on what speed you set the blower switch in the dash on.
This system always seems to confuse people but it's actually a pretty basic system.
As with any electrical problem you'll need the right tools.... A cheap test light and a multimeter will be your best friend.
18243
Willcox
1st.. I would verify the fuse is good.... then i would verify the fuse is making good contact in the fuse panel. Make sure the terminals are not corroded and that the fuse is making good contact.
2nd I'd put the blower motor in a lower speed.. then I would check the purple wire for power... If the purple wire has power then verify the motor ground.
If the purple wire is without power... then go to the dark blue wire and see if you have power.. The inputs to the resistor are Tan, Light Blue and Brown... so when you put the blower switch in the dash in one of the lower speeds it changes which wire gets the power.. the power then runs through the resistor and comes out on the blue wire. Knowing this.. I'd test for power on each of the three wires.. depending on what speed you set the blower switch in the dash on.
This system always seems to confuse people but it's actually a pretty basic system.
As with any electrical problem you'll need the right tools.... A cheap test light and a multimeter will be your best friend.
18243
Willcox
#16
Drifting
Don't know if this will help you but I did a simplified version of that schematic.
1st.. I would verify the fuse is good.... then i would verify the fuse is making good contact in the fuse panel. Make sure the terminals are not corroded and that the fuse is making good contact.
2nd I'd put the blower motor in a lower speed.. then I would check the purple wire for power... If the purple wire has power then verify the motor ground.
If the purple wire is without power... then go to the dark blue wire and see if you have power.. The inputs to the resistor are Tan, Light Blue and Brown... so when you put the blower switch in the dash in one of the lower speeds it changes which wire gets the power.. the power then runs through the resistor and comes out on the blue wire. Knowing this.. I'd test for power on each of the three wires.. depending on what speed you set the blower switch in the dash on.
This system always seems to confuse people but it's actually a pretty basic system.
As with any electrical problem you'll need the right tools.... A cheap test light and a multimeter will be your best friend.
18243
Willcox
1st.. I would verify the fuse is good.... then i would verify the fuse is making good contact in the fuse panel. Make sure the terminals are not corroded and that the fuse is making good contact.
2nd I'd put the blower motor in a lower speed.. then I would check the purple wire for power... If the purple wire has power then verify the motor ground.
If the purple wire is without power... then go to the dark blue wire and see if you have power.. The inputs to the resistor are Tan, Light Blue and Brown... so when you put the blower switch in the dash in one of the lower speeds it changes which wire gets the power.. the power then runs through the resistor and comes out on the blue wire. Knowing this.. I'd test for power on each of the three wires.. depending on what speed you set the blower switch in the dash on.
This system always seems to confuse people but it's actually a pretty basic system.
As with any electrical problem you'll need the right tools.... A cheap test light and a multimeter will be your best friend.
18243
Willcox
Thanks GG
#17
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Nope.. sorry I took a few days off.
I have one for your car about ready to roll.
Give me a few days and I'll post it on the site.
Willcox
I have one for your car about ready to roll.
Give me a few days and I'll post it on the site.
Willcox
Last edited by Willcox Corvette; 09-12-2010 at 11:50 AM.
#18
Former Vendor
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Ok.. here it is.. I worked on it last night and this morning..
1970 Heater and AC wire and vacuum hose schematic.
18243
1970 Heater and AC wire and vacuum hose schematic.
18243
#20
Former Vendor
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Your Welcome Greg-
This is an easy one since it's pretty much a colored version of the AIM one.. You'll find the original in C60 toward the end of that section. Only difference is the AIM version has a wiring mistake on it! Yep.. the wires did not change colors from one end to the other as the original shows..
Thank you again Greg.. really enjoy doing this stuff.. I trying to finish up the Power Steering Control Valve Video.. that one will be nice.. But I had to start over on it and we have been hammered with Shop work so that kills me from getting a helper..
E
This is an easy one since it's pretty much a colored version of the AIM one.. You'll find the original in C60 toward the end of that section. Only difference is the AIM version has a wiring mistake on it! Yep.. the wires did not change colors from one end to the other as the original shows..
Thank you again Greg.. really enjoy doing this stuff.. I trying to finish up the Power Steering Control Valve Video.. that one will be nice.. But I had to start over on it and we have been hammered with Shop work so that kills me from getting a helper..
E