1975 No High Speed Blower Function
Thread Starter
Intermediate
Joined: Aug 2016
Posts: 35
Likes: 5
From: Scottsdale, AZ
1975 No High Speed Blower Function
Hi,
I have been struggling with my blower not working on high speed.on my 75 with A/C. I have read all of the past threads and have tried everything and I can't get the high speed to work. Here's what I can tell you and maybe someone knows what's left.
I have all speeds funtioning except HIGH
I have 12 V on the ORANGE and BLUE wires at the relay when switch is on HIGH.
No power on PURPLE wire to the fan when switch is on HIGH
I have replaced the relay and no change
If I connect the ORANGE and PURPLE wires the fan blows at high speed
Blower Motor is brand new
I have been struggling with my blower not working on high speed.on my 75 with A/C. I have read all of the past threads and have tried everything and I can't get the high speed to work. Here's what I can tell you and maybe someone knows what's left.
I have all speeds funtioning except HIGH
I have 12 V on the ORANGE and BLUE wires at the relay when switch is on HIGH.
No power on PURPLE wire to the fan when switch is on HIGH
I have replaced the relay and no change
If I connect the ORANGE and PURPLE wires the fan blows at high speed
Blower Motor is brand new
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
are you getting 12 volts to the control side of the relay to switch it to high from the dash switch?
The DRK BLUE wire is the high signal from the switch used to close the relay and send voltage from the orange wire to the purple wire to the blower motor
You should get 12 volts between the black wire and the dark blue wire at the high speed relay with the switch in the high position.
Make sure to use the black wire as ground at the relay to validate the ground is good there.
Neal
The DRK BLUE wire is the high signal from the switch used to close the relay and send voltage from the orange wire to the purple wire to the blower motor
You should get 12 volts between the black wire and the dark blue wire at the high speed relay with the switch in the high position.
Make sure to use the black wire as ground at the relay to validate the ground is good there.
Neal
Thread Starter
Intermediate
Joined: Aug 2016
Posts: 35
Likes: 5
From: Scottsdale, AZ
Yes,
I use the black wire to the relay for ground. The switch is on HIGH and all wires are connected to the relay when I check for power. I have 12V at both the DK Blue and Orange wires and no voltage on the Purple so no fan. It doesn't seem to make sense as I believe that if there is 12V at the DK Blue and Orange, then the relay should allow power to the Purple wire, but that doesn't happem.
I use the black wire to the relay for ground. The switch is on HIGH and all wires are connected to the relay when I check for power. I have 12V at both the DK Blue and Orange wires and no voltage on the Purple so no fan. It doesn't seem to make sense as I believe that if there is 12V at the DK Blue and Orange, then the relay should allow power to the Purple wire, but that doesn't happem.
Thread Starter
Intermediate
Joined: Aug 2016
Posts: 35
Likes: 5
From: Scottsdale, AZ
Fuse on Orange wire is brand new and good. I don't think I'd have power on the Orange wire at the relay if it was blown either right? If I connect the Orange and Purple wires directly then the fan blows by the power supplied by the Orange wire.
Safety Car
Joined: Oct 2007
Posts: 4,380
Likes: 1,746
From: Seattle Area Washington
Take your old relay and bend back the 4 tabs on the back and remove cover. You will see a set of contacts inside. Use a points file or some 220 sand paper and clean up the contacts. Sometimes you will need to realign the contacts if there offset.
Put the cover back on and try...
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Thread Starter
Intermediate
Joined: Aug 2016
Posts: 35
Likes: 5
From: Scottsdale, AZ
Mystery Solved!!!!
So I looked at some photos of the wire connections to the relay. All of them have the wires going into a single plug with the exception of the black ground wire. It appeared that the Orange and Purple wires were reversed as the plastic plug is gone on my car so the wires are attached individually. I switched the Orange and Purple wires and voila....I now have all 5 speeds! Thank you all for the responses and maybe someone else is facing the same issue so if you don't have a plug that has the wires which will connect the wires to the relay in their correct positions, then this might be your problem too!!!
So I looked at some photos of the wire connections to the relay. All of them have the wires going into a single plug with the exception of the black ground wire. It appeared that the Orange and Purple wires were reversed as the plastic plug is gone on my car so the wires are attached individually. I switched the Orange and Purple wires and voila....I now have all 5 speeds! Thank you all for the responses and maybe someone else is facing the same issue so if you don't have a plug that has the wires which will connect the wires to the relay in their correct positions, then this might be your problem too!!!
Thread Starter
Intermediate
Joined: Aug 2016
Posts: 35
Likes: 5
From: Scottsdale, AZ
FYI, I replaced my blower motor with a motor out of a later model C4, I think an 86? C4 Fan/blower part # 35334 Rockauto.com I can't remember the year but it has a spade connector that is the same on C3s. If you go to a newer C4, it has a plug that is not compatible with the C3. I had to make a 7/8 inch thick spacer to account for the deeper (same diameter) squirrel cage and this thing cranks! There is a video online for the conversion. Now I can get back to installing the rest of the dash and then finish installing a new drier with the eliminator block and getting the system going again...I did a lot of work under the hood prior to the "in the car" work including installing a new heater core in the box and completely cleaning and painting, where appropriate, the vent tubes and internal box as well as flushing the condenser and evaporator. There is a series of videos that take you through a lot of this... ELH4X4 DOIN' STUFF is the guy for the complete removal and rebuild of the engine compartment componentry. Its a series and
is part 1. The fan blower upgrade video is at
Safety Car
Joined: Oct 2007
Posts: 4,380
Likes: 1,746
From: Seattle Area Washington
Mystery Solved!!!!
So I looked at some photos of the wire connections to the relay. All of them have the wires going into a single plug with the exception of the black ground wire. It appeared that the Orange and Purple wires were reversed as the plastic plug is gone on my car so the wires are attached individually. I switched the Orange and Purple wires and voila....I now have all 5 speeds! Thank you all for the responses and maybe someone else is facing the same issue so if you don't have a plug that has the wires which will connect the wires to the relay in their correct positions, then this might be your problem too!!!
So I looked at some photos of the wire connections to the relay. All of them have the wires going into a single plug with the exception of the black ground wire. It appeared that the Orange and Purple wires were reversed as the plastic plug is gone on my car so the wires are attached individually. I switched the Orange and Purple wires and voila....I now have all 5 speeds! Thank you all for the responses and maybe someone else is facing the same issue so if you don't have a plug that has the wires which will connect the wires to the relay in their correct positions, then this might be your problem too!!!
I would get a new plastic connector housing if I were you and land the wires correctly.
The Orange wire is HOT at all times or until the fuse blows if it shorts against something if it falls off ...
The correct 3 cell connector housing is part number 2962510...
You can find them on ebay LINK: https://www.ebay.com/sch/i.html?_nkw...2624&_osacat=0
If you purchase one that has wires and terminals the terminal has a locking tab that can be bent down so the wire and terminal can be removed from connector housing...
Just bend the locking tab up a little on your terminals so the will lock into the new housing...
