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  #1  
Old 06-06-2009, 01:59 PM
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How easy is it to test AC switches?

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

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  #2  
Old 06-06-2009, 02:23 PM
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Jumper the sw with the two pigtail wires and see if aux fan comes ON low speed.
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Last edited by Arthur Dalton; 06-06-2009 at 02:31 PM.
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  #3  
Old 06-06-2009, 02:59 PM
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No low speed fan

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.
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Old 06-06-2009, 03:01 PM
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Quote:
Originally Posted by MB Nebrasaka View Post
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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  #5  
Old 06-06-2009, 03:12 PM
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tested switch...

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
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  #6  
Old 06-06-2009, 03:19 PM
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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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Old 06-06-2009, 03:55 PM
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Sorry 92 190e 2.3

Have jumper the a/c switch with nothing no clicking at relay or no power to ether side of resistor.
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  #8  
Old 06-06-2009, 03:55 PM
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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.
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  #9  
Old 06-06-2009, 03:57 PM
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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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  #10  
Old 06-06-2009, 04:00 PM
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Quote:
Originally Posted by MB Nebrasaka View Post
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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  #11  
Old 06-06-2009, 04:11 PM
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power

jumper power to one for low then other for high
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Old 06-06-2009, 04:18 PM
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[QUOTE=MB Nebrasaka;2218111]jumper power to one for low then other for high

Yeah...and ?????
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  #13  
Old 06-06-2009, 04:19 PM
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both work

Yes both work. Sorry
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  #14  
Old 06-06-2009, 04:25 PM
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Quote:
Originally Posted by MB Nebrasaka View Post
Yes both work. Sorry

Good ..it does help if you give me the test results cuz I can't read minds anymore since that Kryptonite stuff hit me ...

Change fuses 1 and 3 and then test both fan circuits

High fan test:
Key ON
pull connector off the 2 wire blu sensor at the thermo housing

Low Fan test:

Bridge pigtail wires at pressure sw. again.
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  #15  
Old 06-06-2009, 04:28 PM
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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.

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