76 c3 heater fan switch problem
Thread Starter
Cruising
Joined: Sep 2013
Posts: 10
Likes: 0
From: Sydney Nsw
76 c3 heater fan switch problem
Hi, have had no luck trying to get my heater blower to work,checked all the fuses ect, all ok suspecting the switch so can anyone help out with my test.
Heater switch has two lots of terminals on thr back numbered 1 to 6, have checked these for power in and they are terminal 2,3 and 4 so on checking
Power to terminal 2
Continuity at term 6 in off pos
" ". 1 in speed 1
NO Continuity at any other term in switch speed 2,3 or 4
Power to term 3
NO continuity at any term in off pos or speed 1
Continuity at term 1 in speed 2
Continuity at term 1 in speed 3
NO continuity at any term in speed 4
Power to term 4
Continuity at term 1 in speed 3
NO continuity at any other term in any speed
As I am NO master in electronics can anybody give me some advice thanks ( we are not all stupid in the land down under) just some of us!!
Heater switch has two lots of terminals on thr back numbered 1 to 6, have checked these for power in and they are terminal 2,3 and 4 so on checking
Power to terminal 2
Continuity at term 6 in off pos
" ". 1 in speed 1
NO Continuity at any other term in switch speed 2,3 or 4
Power to term 3
NO continuity at any term in off pos or speed 1
Continuity at term 1 in speed 2
Continuity at term 1 in speed 3
NO continuity at any term in speed 4
Power to term 4
Continuity at term 1 in speed 3
NO continuity at any other term in any speed
As I am NO master in electronics can anybody give me some advice thanks ( we are not all stupid in the land down under) just some of us!!
Burning Brakes
Joined: May 2008
Posts: 948
Likes: 1
From: pensacola fl
Not sure how much I can help but there is a relay under the hood, located on the fire wall. It is silver and located almost in line more with the passenger seat but closer toward the console side if any of this makes any sense. i also believe there is a fuse under the fender on the drivers side but I will have to check some wiring diagrams in the morning and get back with you.
Le Mans Master
Joined: Aug 2006
Posts: 7,425
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
If you apply 12 volts and a good ground to the motor does it turn on?
76 schematic
http://www.vetteprojects.com/bmv/mis...tte%201976.pdf
76 schematic
http://www.vetteprojects.com/bmv/mis...tte%201976.pdf
Melting Slicks
Joined: May 2011
Posts: 2,753
Likes: 119
From: Springfield Missouri
are you sure the motor is good??? There is a relay type thing on the firewall that makes the fan run at different speeds by resisting the 12 volts going to the motor, more resistance slower speed, med resistance med speed, etc. This has small wires across it for resistance, these wires burn into from age, being used etc. Take it loose and see if the wires are burnt into. If they are replace it. The fan should run on low all the time for ventilation, when the control is moved to heat or a/c. If you don't have low speed running check for ground going to motor or motor might be locked up, debris in fan blade locking it up, rats nest or something. It is easy to test for 12 volts at motor with a test light or meter, do you have one of them?? We need to know more to help you, not just your motor doesn't work. You have tested the switch, so you might have a meter. Testing the switch, you must have torn into the console. Your problem might be on the other side of the firewall.
