A/C Compressor & cooling Fan low speed inop Questions.

[pscottb]

Vehicle: Wife's 5/99 built 1999 2.0 New Beetle.

Problem: A/C suddenly inop. Cooling fans and A/C Clutch not working when turned on.

What I've done. Repleced the FCM on a "guess" from reading these forum... that hurt. Problem still exsist.

So, taking a You Tube crash coarse in Mult-Meter use I found an awsome Diag for the fans online.
1) Jumped Thermo Swt Harness, tested fans "Low Speed" (Pin 1-2 key off) failed test!,
2)High Speed (pin 2-3 key on)Passed Test!
3)Checked FCM: Jumped plug and did Hi & Low jump test from plug through FCM to Fan Harness ends Low & High passed test. FCM tested OK!
4)Direct current fan test: Grounded #3,Powered Pin 1, High Speed PASSED. Low speed, pin 2, FAILED
5) Stood in awe at the education and upgrade in my ability I got for free on this sight! A million thanks!(Amazing how not having money to pay a tech can motivate to educate!)
SO after all the bable here's the questions:

1) Can I be sure that replacing the fans will signal the FCM that all is well and to PLEASE release my A/C and unhappy wife from your GRIP!

2) Do I need factory fans or any decent two speed after market will due the job.( maybe stupid thought but I don't know if the factory resistance measurement from the low speed resistor is in sync to the FCM "like a glove" and some fans won't work)

I'll wait as patiently as my "hot" wife...get it Hot.. will let me...for an answer!

[MyOtherRidesAVette]

Compare those tests to the Bentley cooling fans and thermal-switch testing toward the end of this Coolant System Diagnostics section.
http://newbeetle.org/forums/attachme...thru-19-12.pdf

I don't think anyone would be so bold as to say that replacing the fans will end your woes, but if they are bad, they are bad.

As to aftermarket fans, there is a thread where some one did aftermarket and larger fans but had to create new mounting methods etc. I'm sorry, but for the most part, I'm a believer in OEM quality and replacement. It was maybe two-three months ago, search "fans" (OMG hundreds and hundreds) or maybe "fan relplacement", three letter words don't search.

MORAV

[D2Beetle]

Lots of DIY work, congratulations! I hope the fan turns out to be your only problem; however you might want to check the sensor in the radiator as well.

[MyOtherRidesAVette]

Originally Posted by pscottb

So, taking a You Tube crash coarse in Mult-Meter use I found an awsome Diag for the fans online.

Of course the links would have been nice!

[blkbug]

srry to highjack but does someone have the diagram for troubleshooting AC on the bently and could post the link to it?

[MyOtherRidesAVette]

Originally Posted by blkbug

srry to highjack but does someone have the diagram for troubleshooting AC on the bently and could post the link to it?

You could have just p/m'd me!

For what ever reason, I can't find or pull up the troubleshooting flow charts on my Bentley Repair Manual, they must be there, but I'm having ongoing issues, that I need to get resolved with eBahn. My search feature returns the same one thing, no matter what the search, and worse, it's French. In the meantime, maybe this will help. Anybody know where they've hid these damn things?

M.

[pscottb]

Good point...Sorry. I was another computer & didn't think of that. It claims to be the Best Tutorial.. don't know. It was enough for me. For being the best though I found It didn't even explain the other way to test current by grounding a lead and probing the wire or plug.(dc) It only demonstrated "tapping" into the wire method. Hope you like.

THE BEST Multimeter tutorial (HD) - YouTube

[pscottb]

Ok. I'm printing it now. Can I least surmise that the fans are bad seeing that direct power right to the fan motors showed low speed "failure"? After all direct power is direct power.
With that "fact" in mind then these test can show if there is another problem with the a/c turning on and/or what may have caused the low power resistor to fail?

[pscottb]

Ok. Re-ran FCM test & Fan test. Fans were bad /no low speed. Replaced the fans. New Fans work perfect before & after install!

I also have power to the white wire on the HP switch(G65)as test suggested.

Lets talk A/C Compressor: I have power to the compressor (as even before I replaced the fans..) I unplugged the compressor and Ohms tested the clutch/compressor leads.. nothing, nada, zip..ziltcho.. no readings..

What conclusion can I draw? Clutch is bad? Is there anything else hidden I don't see that can be signaling that compressor not to engage, does not all signal/power flow into the main harness- two wire lead?

[MyOtherRidesAVette]

Originally Posted by pscottb

Ok. Re-ran FCM test & Fan test. Fans were bad /no low speed. Replaced the fans. New Fans work perfect before & after install!

I also have power to the white wire on the HP switch(G65)as test suggested.

Lets talk A/C Compressor: I have power to the compressor (as even before I replaced the fans..) I unplugged the compressor and Ohms tested the clutch/compressor leads.. nothing, nada, zip..ziltcho.. no readings..

What conclusion can I draw? Clutch is bad? Is there anything else hidden I don't see that can be signaling that compressor not to engage, does not all signal/power flow into the main harness- two wire lead?

I'm not sure how you would Ohm test a compressor (I'd have to do a little Googling), but since you do have switched power to the compressor and it is not engaging, one or the other are bad. They are sold as a single component. I'm assuming your not rebuilding it, so knowing what is wrong with it, is kind of a moot point.

M