12 Vdc to compressor

fgcox1

You are correct. Bad labeling on the schematic. I guess it is a defrost switch for the evap but they should label as such.
I have 12 v in and out of that thermoswitch but nothing at the dryer/switch.
Checked and no continuity on the Black/Yellow.
Will trace it tomorrow as it's getting to hot outside.
Tnx for the steer!

Cusser

"I have 12 v in and out of that thermoswitch but nothing at the dryer/switch.
Checked and no continuity on the Black/Yellow."

Check first that the L/W (blue/white) wire from the AC relay actually grounds through the AC switch L/Y (blue/yellow) wire when the AC switch is "on". The blower resistor and the AC switch cannot be overlooked, may not be a bad AC relay itself. Study/print the AC wiring circuit.

fgcox1 - does your blower fan operate in ALL four speeds?

fgcox1

Chased the wiring back from the dryer, I missed the connector that barely comes thru the firewall beside the drain hose. Plugged it up and everything is fine.
Thanks for all of the ideas!

Cusser

Great !!!

kz6fittycent

I found this thermoswitch and may give it a shot as a replacement since OEM ones are hard to find.

MazdaMitch

kz6fittycent Damn thats a good find and good price. I may get one to have on hand.

MazdaMitch

kz6fittycent I wonder what the cut off temp is and can it be adjusted? Not seeing any information about that.

kz6fittycent

It's reviews say it works really well. It's not adjustable. I just bought it and will report back. I'll likely create a video for my channel to illustrate how to install it. It'll require some minor mods I think but nothing big.

Cusser

"I wonder what the cut off temp is and can it be adjusted? Not seeing any information about that."

Most of these do not have adjustments as they are to "open" the compressor circuit when evaporator temperature get to just above freezing, and then "close" the circuit when the evaporator temperature gets to maybe about 38F.

However, where the sending bulb gets placed inside the evaporator can make a little difference.

kz6fittycent

I tried to upload the video, but no go. Here's a link to watch my new thermoswitch working!

MazdaMitch

kz6fittycent that's great news. Do you have a thermometer you can stick in the vent and see where it may be turning off at?

kz6fittycent

MazdaMitch I do - but I'm pretty much in for the night. Let me do some more checking tomorrow. It might be misleading since the temps are dropping here in TX, but I'll do what I can. As I was driving around town just now, it was very comfortable (COLD).

Another thing I intend to try and figure out is an idle control motor so I can set my idle with everything off, and let the idle control motor switch on when the AC comes on, then it can ramp the RPMs up a little to keep things steady.

kz6fittycent

Alright just to close this loop on my vent temps:

Ambient temps currently 71F and 92% humidity

With recirculation - 39/40F cutoff -> 45/46F ac pump activated
With fresh air - 41/42F cutoff -> 49/50F ac pump activated

MazdaMitch

kz6fittycent I don't feel like that's going to be sufficient in the summertime.
I would expect it to at least give you 36° vent temps if it's cutting off around 33.8° like it should.

kz6fittycent

It's set to cutoff at 38F IIRC. I'll add that dealing with a frozen evaporator is less ideal than allowing it to cutoff like it's supposed to do. We'll see. Temps keep dropping, so it's hard to say exactly what will be the result in warmer/hot weather.

Fact is, my AC is COLD typically. My son usually asks me to turn it off lol. My temps usually ran in the low 30's before it'd freeze up.

MazdaMitch

Yeah it might do okay.
It's currently 71 here with 81% humidity.

I'm driving and I'm running the AC and the first cut off the vent temp was about 38° and then when it rose to 43° it turned on again.

Then it got down to 37° and then it turned off again at 42°. These are vent temps.

This is about the average for right now I suppose sometimes when it's hotter it gets lower like 35° so this tells me yours probably working just fine.

Cusser

The Cuss says: sounds good to me, don't mess with it !!!