I want to test the two switches on the receiver/drier. Both the thermoswitch and the AC temp switch. My auxillary fans won't come on and because of this the compressor won't run. Which switch controls this function?

Thanks

Jumper the sw with the two pigtail wires and see if aux fan comes ON low speed.

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A Dalton

My low speed fan does not work also but compressor does come on but i switch it off because my a/c gauges some high side going over 400.

Chevy ????

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A Dalton

when I connect the two pigtails together, key in the on position, the relay in the fuse panel clicks...but no fans come on? Does this mean the switch is good or bad. Is the relay good or bad.

Chuck

It means you have verified the relay coil circuit as OK, and you now have a Load side problem.
That usually means a fuse or the wries at the Resistor .R15


Jumper from bat Pos to R15 :
To single wire terminal on R15 gets low fan
To 2 wire therminal on R15 gets high fan

If No to either , the fan is bad
If Yes to high fan , and No to low fan..the R15 is bad.
If Yes to both sides , then the Aux fan fuse is suspect.

You want to list model/year.......

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A Dalton

Have jumper the a/c switch with nothing no clicking at relay or no power to ether side of resistor.

Then fuse is suspect.

But first, bring a jumper from Bat + to each side of R15 ...one at a time .
One side will get high fan, the other low..

Try that first

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A Dalton

jumper power to one for low then other for high

O.K. Tried a wire from battery to one wire terminal, then two wire terminal: no to both. I made sure I was getting power by touching wire from battery to metal: got spark.
Does this mean both of the auxillary fans are bad? Will the fans not coming on mean the compressor will not come on? Is it common for these fans to go bad?
Thanks for your help. Bear with me.

Sorry, this is for a '93 190e 2.6. Where can I find the R15 resistor? I'll test this next if you'll show me where it's located.

Down in the left/front of engine compartment..usually behind the left headlamp area.

If not , try around the booster area.

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A Dalton

i'm sure it will be me....wow, talk about a self-fulfilling prophecy.

Alright. Tapped on the fan bearings (passenger side) with a rubber mallet. Loosened it up enough to spin by hand, still a little "crunchy" but will spin by hand. The other fan (driver's side) spun by hand at first try.
Tried to jumper...with no success.
What now?

Chuck

OK

Two possibles ..
One is both fans are bad and you have only noticed the problem when the last one went out..meaning they most likely did not crap at the same time..

Second is you have a bad/poor connection between the R15 terminals and the fan motors.. The motors have a common plug for both, so you may want to check that plug
it is tucked in behind the fan cage and hard to get to, but look around for it.

Also make sure the wires are tight on the R15 where you jumpered 12 V. pos to.
If you put a test lamp at the terminal oppisite the one you are jumping to, that will confirm you have a good jumper feed.

My guess is bad fan motors.

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A Dalton