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I’m putting boxes of heater and a/c parts back in my 66 cutlass (they came in a box in the trunk when I got the car 20 years ago with a blank off plate the firewall and I always just lived with it…until now). My blower switch has 4 positions on the front… none indicate off (This is confusing on it’s own to me as the only other switch on the control head is actuated by the a/c lever - to power the a/c compressor clutch). This said, with the switch rotated full counterclockwise (all the way up on “hi” as in the photo) none of the electrical terminals on the back are connected to each other, i.e. the electrical part of the switch seems to have Off,lo,Med,Hi). I’m hoping someone will help me understand this so I can wire it up (I have a manual and while it has good vacuum diagrams I can’t find an a/c blower electrical diagram at all in the hvac section and the one in the electrical section appears to be incomplete/incorrect since it doesn’t show any a/c or a blower relay for hi speed). As always, I appreciate the help. My blower resistor has 4 terminals. Red text correlates to continuity between pins on back of switch, see switch back pic. Fan switch electrical part numbered for reference. Manual a/c chapter where I can’t find detailed blower operation info or wiring diagram.
Last edited by jackedolds; December 22nd, 2023 at 05:24 PM.
That color wiring diagram shows the base-equipment heater-only wiring. A/C wiring uses a separate blower high speed relay. High speed on the blower motor is powered by a completely separate fuse, which is likely your problem. This diagram is from a later model, but the blower motor wiring pretty much the same on yours. Note the separate 30A fuse in the upper RH corner.
Joe - your diagram shows 5 wires off the blower switch. This is what I expected based on my switch faceplate (4 speeds with no off position) - thank you.
This said, my switch only has 4 electrical terminals to land wires on - see pic. I also can’t find the “master switch” anywhere on my hvac control head (was this actuated by the top lever?). This is really the nature of my question.
It seems someone put the electrical switch part from a basic 3 speed fan on my 4 speed fan car (hell, given the other non olds parts I’ve pulled off this thing it may not even be from an olds!) . If someone has a picture of the “master switch” and the electrical terminals of the correct switch for my faceplate it may help clear it up.
Supernice88
The ac section of the manual shows routing so I think I’m good. I have what appears to be most of the the control head to blower resistor/relay/fan harness and there are more wires from switch to resistor than I have terminals for on the switch. This is why I think there are incorrect/missing electrical parts on my control head.
The point of my prior post was to show you the high speed blower relay and separate fuse. Did you check those? In any case, here is the 1966 control head.
I’m not trying to diagnose why something doesn’t work, I’m trying to install parts that came in a box and wire them.
Your wiring diagram confirms that I have the wrong speed selector switch and the illustration in the last post diagrammatically shows me where the master switch should be. So those questions are answered - thank you.
Can you tell me if it’s the top lever on the control head that actuates the master switch (if not which lever does it)?
If you, or someone, has an A\C car will you please take a photo of the terminals on the back of the fan speed selector switch and a photo of the “master switch” so I know what I’m hunting for at swap meets ( an actual picture, not a book illustration). Thanks all - Merry Christmas!
Last edited by jackedolds; December 23rd, 2023 at 10:22 AM.
One more time. The wiring diagram I posted above is NOT the one for your car, it was intended only as an example. Your car doesn't have an OFF position on the switch. That Master Switch serves as the "fifth" terminal.
In your first post you indicated that the blower didn't work in the HIGH position. That is what I am trying to address.
I don’t recall saying I don’t have high speed, but I can see how you might have interpreted that. I should’ve worded the original post differently.
I recall saying with the selector on high there are no paths of continuity through my switch. Turning a high speed blower relay on still requires that the selector switch power the relay coil via a path of continuity through the speed selector switch (and the actual blower power on High comes from the dedicated fuse). The example diagram you provides shows EXACTLY this. The power feed to the 5 terminal of the speed selector switch comes from the master switch. The speed selector switch has 4 paths of continuity. My switch only has 3 paths of continuity 😉.
Anywho, I appreciate the help. Thank you.
If you’re an admin and you can delete this post I’ll repost in a clearer manner what I’m looking for.
Last edited by jackedolds; December 23rd, 2023 at 11:45 AM.
I don’t recall saying I don’t have high speed, but I can see how you might have interpreted that. I should’ve worded the original post differently.
The very first photo, where is says "Nothing" next to the high speed position, pretty much implies that is the problem. Also the fact that this is a very common question, since most people are unaware of the separate power source and fuse for the high speed position.
December 22nd, 2023, 03:32 PM
