Heater Switch

[Damon23]

Does anyone here know the right way to test this switch? I move it and get no activity from the blower. So, I dropped the inner fender and put voltage straight to the motor and it worked. So, that would lead me to believe the blower was good. Although the air flow was not all that spectacular it moved air. The car was not running either so that may have had something to do with the airflow situation. Connected to the motor is two wires, tan and a black. Tan must be positive and black negitive. I used my meter and put the switch in each location and got no voltage at the wires. Now depending on the locaton of the switch I get continuity in places but have no idea what i'm reading.

[Damon23]

Well, i'm going to have to call it a bad switch. I have voltage going to the switch just nothing going to the blower. Since I have the fender well down I pulled the blower and am going to replace it since they made it so convient. Besides, the terminal on the blower was loose in the case so I might as well. I was given some good advice by the person I bought the car from, he said to make sure and grind the paint off the ground terminal on the outside of the blower to make sure it is a good ground. So I guess a new switch is in order. The previous owner thinks he has one so he is going to send that along with the metal brackets for the rear spoilers. I may keep those things after all. The car is jacked up on one side with the fender well hanging down and the wheel off. I can just see how this is going. Might as well do the brakes since the wheel is off, might as well detail the wheel wells while it is up there too, hey might as well remove the front clip get all the junk out of the crevaces and detail the motor. The ever so unpopular snowball affect. I will do the brakes but that will be it untill after paint. I did however manage to replace the oil pressure sender and the temp sender today, and got a couple of handfulls of pinestraw out from the bottom of the front fender. I will spray some wd-40 in there now that it is all cleaned out. So today was productive.

[outlaw77LT]

If he don't I'll send you the one out of mine with the control lens.

[D21458P]

Make sure to check fuses as well.

[Damon23]

Yep, fuse was fine. I have a new switch coming from GM. You can read my post in the backyard and see about the fiasco i've had this evening. So, i'll wait for that switch to come in and swap out this blower motor and try again Wednesday. Anyone know what the blower cut off relay is for?

[Damon23]

Alright. The dealership actually had a switch in stock. So, $13 later i'm in business. I installed the new blower motor, replaced the fuse and hooked up the new switch. Presto, I had a air movement but not for long. ZAP, fuse blew again on high. So I turned the slider ot the off position, checked all the wiring I could and found a lose wire in the blower cut off relay harness. Replaced the fuse again hooked everything back up and air was moving again. But wait, the switch was not doing anything to control it. The fan was just running. I could tell a little varience in the fan speed as I went up and down but no change. Hmmmmm.........the slider was set to off as well. So I move the slider and ZAP, fuse blows and I come inside.

[Zachs Bank]

Man I feel for you cause there aint nuthin worse than chasing a wiring prob. Luck!!! Theres a short somewhere and they aint fun to track down.

[Chick]

Found this at NastyZ28 from a '78 model, didn't know if you had seen it. Should be basically the same.

http://www.nastyz28.com/camaro/wire/78w-acopt.jpg

Not sure which part is the blower cut off relay you're referring to. Do you see it on the diagram?

[Damon23]

Alright I see it. Thanks. I'll search that a little more.

[Damon23]

From that diagram it appears I have a short on number 968, the dark blue wire from the switch to the blower cut off relay. I dont know if it is supposed to be shorted or not. The relay has a ground already.

[Chick]

My husband is an electrician (non-automotive), but I'll ask him tonight to look at the diagram. Is that the blower cutoff relay that 968 terminates in? Have you tested the relay if so?

[Damon23]

Yes, that is the relay. I think i've found it. The selector switch I think is bad. Whenever I move it from a/c to heat or move it in general, that is when the fuse blows. I was given some info and have to test the selector. I just hope I did not fry the new speed control switch. At least GM still has them.

[Chick]

standing by... ;)

[Camaro6662]

Yes, that is the relay. I think i've found it. The selector switch I think is bad. Whenever I move it from a/c to heat or move it in general, that is when the fuse blows. I was given some info and have to test the selector. I just hope I did not fry the new speed control switch. At least GM still has them.Bingo thats what I was thinking :D

[Damon23]

Alright, ran the jumper to take out the selector (jumped tan/brown to tan on the selector switch) and here is what i've found. No fuse blown, will not change speeds untill you run it up to hi, wont work on high but will then work on MED 2, again with no fuse blown. I feel like we are moving in the right direction. Selector bad and maybe the hi speed cut off relay I bought is bad out of box? Or maybe i fried the switch cause when I installed the old one back it does the same thing. So, getting no low, med 1, med 2 only after it take it to high and back down, and does not work on high.

[Chick]

I'll have to check with him tomorrow. Was late when I saw this reply. It's more likely that both relays you have are good and the problem is something else (odds). I know you can test relays cause he tested mine tracing my ABS light. He showed me how, but meters are greek to me.

[Damon23]

I ordered a new blower motor resistor. We will see on Tuesday if that helps.

[Chick]

From Greg's BD thread:

I dont know if you read your PM's lately but no blown fuses, so thats your birthday present from me.

You figure it out?

[Damon23]

No not yet. Waiting on the blower motor resistor to show up. I need to find a selector assembly for the car cause I know that is one of the problems. I dont know what else there is to replace after this resistor. I guess is would be wiring but that has nothing to do with changing speeds, it would all be in the selector.

[Chick]

Wonder if contact cleaner spray would work on the selector? Whadda ya think? Kenny? Guys?

[Damon23]

I dont know. Unless some metal shavings or something got in there. I dont think gunk would cause a short. I dont know. I'll wait and see what happens once I get the new resistor and go from there.

[Camaro6662]

Wonder if contact cleaner spray would work on the selector? Whadda ya think? Kenny? Guys?
It would be worth a try...cheap fix

[Damon23]

Yeah. Whats another fuse.

[Zachs Bank]

Its the least expensive, Give it a shot.

[Damon23]

Yeah, I will tomorrow when the resistor comes. I still need a selector assembly for my car though. Who would have though, to get the blower to work I have to go thru all of this? So now, I'll have a new speed switch, blower, high speed cut off relay, blower motor resistor, and the only thing left will be a thermal relay which no one seems to have or know anything about but is on the diagram.

[Damon23]

The new resistor did not work. I wonder if I fried the new switch I installed when I was blowing fuses cause the old switch and the new switch are doing the same thing and so is the high speed cut off relay. Works in one speed low, and then will only work in med 2 but you have to get the switch just right.