A/C - compressor wiring

[Burntboot]

Have decided it is time to try to resurrect the a/c.
The idler was seized solid and the belt missing, both of those situations have been corrected.
However the clutch does not engage.
Supplying 12v to the clutch causes engagement, however I have no power going to the compressor (and the connector was green)

Page AC-13 trouble shooting chart clearly states that the first thing to check is the FL 30A CDS, it then references page AC-4.
AC-4 is a diagram for 2wd single AC system, mine is of course 4WD dual system.

I have found no other reference to this mysterious 30A fusible link, though AC-4 does clearly show
FL 60A am1 plus the 2 at the battery (FL 1.25B and FL 20B) but no mention of the 30A??
AC-13 seems to be the only reference to this fusible link I can find.

Any of you guru's know where to start the hunt for this elusive fusible link, or if it actually exists.

Meantime I will look for the AWOL meter to eliminate the Mag-clutch relay, though I did pull it for a visual, looks brand new inside, can't see it being an issue but....
Thanks

[timsrv]

It could be any number of things, but the 1st thing I'd check is the system pressure. If the AC system hasn't been used for a long time, it's likely that the freon has leaked or permeated out of the system. If that's the case, then the clutch won't engage due to the low pressure switch being open.

Because this is the most likely cause, it's probably not worth going into other troubleshooting until system pressure has been verified. If the pressure is low, you may wish to bypass that switch to verify compressor operation before recharging. Tim

[Burntboot]

Thanks Tim.
That does make sense, AC was never my forte and while I used to have a shop I was comfortable with, that is no longer the case. Only to say that I no longer have access to AC equipment.

What are your thoughts on Dura-cool products?
Their product claims sound to good to be true.
That always makes me suspect, but every major retailer is carrying it now, so perhaps there is some validity to their claims?
I believe some of their kits have gauges, but no idea if that is a worthwhile route to go down.

For what it is worth, PO converted to R134 many years ago, so theoretically that is one less thing to worry about, if it was done right, that is.

[timsrv]

Sorry, but I have no idea about anything other than R-12. I dug in a long time ago and stocked up on R-12. I still have a lot left and don't plan on changing over to anything else (at least not on vehicles designed to run on R-12). I figure if it was designed for R-12, then it's staying R-12. I do have one newer vehicle now that came from the factory with R134, but so far I haven't needed to do anything to it.

Until that one needs service, I probably won't be messing with R134.........I don't even have a gauge set for that yet. Tim

[Burntboot]

I hear ya, Tim.
R12 is most desirable for anything that was made to run on it.
R134 just isn't the same, doesn't run as cold.
We have had draconian rules regarding it use, storage and sale of it since the mid nineties.
I think selling heroin carries fewer penalties.

[timsrv]

For what it's worth, turning your AC on once a month (even for a couple of minutes) helps it keep the charge. Most of the rubber lines have pores and/or pin-holes that allow the freon to slowly leak away. Running it for a few minutes circulates compressor oil with the freon and that helps to temporarily plug up these potential leaks. This is the primary reason automotive AC systems lose their charge (after a prolonged period of non-use). The longer they sit the faster they leak. Tim

[NEC]

regarding alternative refrigerants: I have had great results with "freeze 12" (google it). It is a refrigerant that has much more similar characteristics to r-12 than 134a. The stuff is reasonably priced too. You will need a r-12 license to buy it in the states, though. Technically speaking it can be added to a r-12 system without any performance issue or problems, however, if you want to do a proper (legal) conversion that will satisfy the environmental hippies you would have to completely evacuate your system and change the service valves to fit the new freeze 12 system. If you use a can side tap you can get around the proprietary fittings and use your old r-12 equipment to charge your system. I am currently running around 1/2lb of freeze 12 mixed with my r-12 and it is working fine.

[vietnamvanman]

Have decided it is time to try to resurrect the a/c.
The idler was seized solid and the belt missing, both of those situations have been corrected.
However the clutch does not engage.
Supplying 12v to the clutch causes engagement, however I have no power going to the compressor (and the connector was green)

Page AC-13 trouble shooting chart clearly states that the first thing to check is the FL 30A CDS, it then references page AC-4.
AC-4 is a diagram for 2wd single AC system, mine is of course 4WD dual system.

I have found no other reference to this mysterious 30A fusible link, though AC-4 does clearly show
FL 60A am1 plus the 2 at the battery (FL 1.25B and FL 20B) but no mention of the 30A??
AC-13 seems to be the only reference to this fusible link I can find.

Any of you guru's know where to start the hunt for this elusive fusible link, or if it actually exists.

Meantime I will look for the AWOL meter to eliminate the Mag-clutch relay, though I did pull it for a visual, looks brand new inside, can't see it being an issue but....
Thanks

When i bought my VAN, all the AC wiring were modified by.... previous owners. I did restore the AC wiring and fixed the "clutch not egange" problem. So i suggest following bellow sequence starting from #1.



MY AC before failed on #5 because of a faulty transistor inside the AC amplifier did not pull #5 ground so IDLE did not go up -> magnetic did not engage. I replaced the transistor and it worked.

If you don't have that problem and IDLE goes up to ~900RPM already but still has no voltage at #7 then try to turn the RPM knob on the AC amplifier clockwise all the way. Hope this help !

Tinh