67 A/C Problem
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 3,078
Likes: 101
From: Riverhead New York
67 A/C Problem
The Heater Blower Motor on my car was working fine. Out of the Blue while driving with the A/C running the HBM stopped. I'm just in from trouble shooting and am Stumped. Here's what I found. 30 AMP Fuse by the Horn Relay was Fried. Didn't Blow, just detached from one End Connector on the inside of Fuse. Could have been a Defective Fuse. Replaced this Fuse and A/c Comp. does Kick in. I turned the car off, (Sidepipe car), and with the Key on I can Faintly Hear the Blower spinning in only the first and second speeds. Go to High and it stops.
Thoughts and Opinions welcome. Thanks, Al W.
Thoughts and Opinions welcome. Thanks, Al W.
Drifting
Joined: Oct 1999
Posts: 1,665
Likes: 476
From: Corrales NM
Al,
Did you check the blower resistor pack to see if all the resistors are intact and operating correctly? It is located on the top of the evaporator box. I had problems with mine. It gets real hot when the blower is in the lower fan speed modes and it is proned to failure.
-Bruce
Did you check the blower resistor pack to see if all the resistors are intact and operating correctly? It is located on the top of the evaporator box. I had problems with mine. It gets real hot when the blower is in the lower fan speed modes and it is proned to failure.
-Bruce
Racer
Joined: Apr 2008
Posts: 439
Likes: 2
From: PASADENA CALIFORNIA
The Heater Blower Motor on my car was working fine. Out of the Blue while driving with the A/C running the HBM stopped. I'm just in from trouble shooting and am Stumped. Here's what I found. 30 AMP Fuse by the Horn Relay was Fried. Didn't Blow, just detached from one End Connector on the inside of Fuse. Could have been a Defective Fuse. Replaced this Fuse and A/c Comp. does Kick in. I turned the car off, (Sidepipe car), and with the Key on I can Faintly Hear the Blower spinning in only the first and second speeds. Go to High and it stops.
Thoughts and Opinions welcome. Thanks, Al W.
Thoughts and Opinions welcome. Thanks, Al W.
Look at the relay on the evaporator box and the wiring to it. This relay controls high speed blower operation. It sounds like something internally in the relay may have shorted if it fried the 30 amp fuse. This 30 amp fuse is only for high speed blower operation and does not effect the operation of the A/C Compressor. Check the Black/orange wire in the connector to this relay to see if it is "Hot" when the ignition is "ON" and the blower switch is in the "HIGH" position. If not, then look at the blower switch and associated wiring. With the ignition "OFF", you can also momentarially jumper between the RED and PURPLE wires of the relay plug and the blower should run on HIGH SPEED. The RED wire should be "HOT" all the time.
I hope this helps,
Chris, CWPASADENA
Racer
Joined: Apr 2008
Posts: 439
Likes: 2
From: PASADENA CALIFORNIA
Al,
Did you check the blower resistor pack to see if all the resistors are intact and operating correctly? It is located on the top of the evaporator box. I had problems with mine. It gets real hot when the blower is in the lower fan speed modes and it is proned to failure.
-Bruce
Did you check the blower resistor pack to see if all the resistors are intact and operating correctly? It is located on the top of the evaporator box. I had problems with mine. It gets real hot when the blower is in the lower fan speed modes and it is proned to failure.
-Bruce
It is my understanding this resistor pack is only in the circuit for LOW and MEDIUM blower speed. The relay disconnects the resistor pack and connects the blower motor to full 12 Volts for HIGH SPEED.
Chris, CWPASADENA
Race Director
Joined: Apr 2005
Posts: 11,246
Likes: 2,111
From: Bowling Green, Kentucky
The Heater Blower Motor on my car was working fine. Out of the Blue while driving with the A/C running the HBM stopped. I'm just in from trouble shooting and am Stumped. Here's what I found. 30 AMP Fuse by the Horn Relay was Fried. Didn't Blow, just detached from one End Connector on the inside of Fuse. Could have been a Defective Fuse. Replaced this Fuse and A/c Comp. does Kick in. I turned the car off, (Sidepipe car), and with the Key on I can Faintly Hear the Blower spinning in only the first and second speeds. Go to High and it stops.
Thoughts and Opinions welcome. Thanks, Al W.
Thoughts and Opinions welcome. Thanks, Al W.
Low and Medium blower speeds are regulated through the Indak resistor block that fits in the outer AC evaporator cover (engine compartment). The high speed is controlled through a blower relay that is close by the Indak and that looks like a horn relay with a black cover. This relay may have a problem...causing the blown/destroyed in-line fuse.
Also blower motor itself may have a problem (short) at the high speed windings, or at the higher volts/amps load for high speed. You might try installing a new fuse and going directly to the blower motor terminal (use a thick jumper wire - #10 or #12) to see if you can get the blower to go full speed. Don't try this without the fuse. If the blower works okay, then checkout the relay next.
Larry
Race Director
Joined: Apr 2005
Posts: 11,246
Likes: 2,111
From: Bowling Green, Kentucky
Al:
If you use the jumper wire I talked about, make the final connection at a point where a little arcing/sparking won't be a problem...ie. don't make the final connection at the blower connection terminal. You don't want to burn/damage this connection.
The voltage/amp surge when you make the final connection to the blower motor will create some arcing. So don't dally........or consider using a common wall light switch in-line to energize power.
Larry
If you use the jumper wire I talked about, make the final connection at a point where a little arcing/sparking won't be a problem...ie. don't make the final connection at the blower connection terminal. You don't want to burn/damage this connection.
The voltage/amp surge when you make the final connection to the blower motor will create some arcing. So don't dally........or consider using a common wall light switch in-line to energize power.
Larry
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 3,078
Likes: 101
From: Riverhead New York
Al:
If you use the jumper wire I talked about, make the final connection at a point where a little arcing/sparking won't be a problem...ie. don't make the final connection at the blower connection terminal. You don't want to burn/damage this connection.
The voltage/amp surge when you make the final connection to the blower motor will create some arcing. So don't dally........or consider using a common wall light switch in-line to energize power.
Larry
If you use the jumper wire I talked about, make the final connection at a point where a little arcing/sparking won't be a problem...ie. don't make the final connection at the blower connection terminal. You don't want to burn/damage this connection.
The voltage/amp surge when you make the final connection to the blower motor will create some arcing. So don't dally........or consider using a common wall light switch in-line to energize power.
Larry
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Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 3,078
Likes: 101
From: Riverhead New York
Took me a whole week to find the Time to work on the car. (Grandkids are more fun!). Changed out the High Speed Relay as I had a spare and Blew the Fuse again. No wonder though, I had a 25AMP Fuse where a 35AMP belonged!
Went to Auto Zone and all they carry in an AGC is up to 30AMP.. Put one in and all seems fine. Tomorrow I'll go to my FLAPS and get some 35's. Thanks to everyone who Helped me with this problem. Al W.
Went to Auto Zone and all they carry in an AGC is up to 30AMP.. Put one in and all seems fine. Tomorrow I'll go to my FLAPS and get some 35's. Thanks to everyone who Helped me with this problem. Al W.
Racer
Joined: Apr 2008
Posts: 439
Likes: 2
From: PASADENA CALIFORNIA
Took me a whole week to find the Time to work on the car. (Grandkids are more fun!). Changed out the High Speed Relay as I had a spare and Blew the Fuse again. No wonder though, I had a 25AMP Fuse where a 35AMP belonged! Went to Auto Zone and all they carry in an AGC is up to 30AMP.. Put one in and all seems fine. Tomorrow I'll go to my FLAPS and get some 35's. Thanks to everyone who Helped me with this problem. Al W.
Went to Auto Zone and all they carry in an AGC is up to 30AMP.. Put one in and all seems fine. Tomorrow I'll go to my FLAPS and get some 35's. Thanks to everyone who Helped me with this problem. Al W.
CONGRATULATIONS!!!
It sounds like you found the problem. Be sure all the wire connections are CLEAN and TIGHT. Be sure to also check the fuse holder. This circuit pulls a lot of amps when the blower is on Hi-Speed and everything needs to be good so you do not get overheated connections.
Take Care,
Chris, CWPASADENA
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 3,078
Likes: 101
From: Riverhead New York
CONGRATULATIONS!!!
It sounds like you found the problem. Be sure all the wire connections are CLEAN and TIGHT. Be sure to also check the fuse holder. This circuit pulls a lot of amps when the blower is on Hi-Speed and everything needs to be good so you do not get overheated connections.
Take Care,
Chris, CWPASADENA
Years back I would have Blasted threw this in a matter of minutes. Most Diagnosis of problems with these cars aren't too hard to complete. Oh well, I'll take Confusion and Old Age anyday!
Al W.
Racer
Joined: Apr 2008
Posts: 439
Likes: 2
From: PASADENA CALIFORNIA
Thanks Chris, This was an easy Fix and hopefully it will hold. I'm just Mulling over in my Mind that as I age I suffer from Paralysis by Analysis.
Years back I would have Blasted threw this in a matter of minutes. Most Diagnosis of problems with these cars aren't too hard to complete. Oh well, I'll take Confusion and Old Age anyday! Al W.
Years back I would have Blasted threw this in a matter of minutes. Most Diagnosis of problems with these cars aren't too hard to complete. Oh well, I'll take Confusion and Old Age anyday!
Al W.I know what you mean! I am 71 and sort of retired but I had worked on this stuff (mostly Mid-Years and a lot of A/C Cars) for many years. I probably would have had to do a little more research to come up with a diagnosis for your problem but recently I had just finished going thru all the A/C and associated wiring on my own '65 and it was "fresh" in my mind, about as "fresh" as things get these days. Your car is the same as a '65 in this area.
I see where you have had your car for a long time. It is good to see long time owners still enjoying their Corvettes and working on them. Often times, these cars would just sit in the garage. As you know, these are very good cars and need to be driven and enjoyed.
Take care and enjoy your Corvette.
Chris
