96 A/C question

The A/C doesn't work on my wife's 96 TS. I did a search and found the schematic. Not sure which relay is for the A/C circuit, yet. Here is what I have done so far. Verified fuse is good. When the A/C push button was pushed, the blower fan came on. I jumped the low pressure sensor switch. One circuit the cooling fan came on. The other circuit the compressor clutch did not engage. I injected 12v directly to the compressor connector. The clutch engaged. What should I tried next? Thanks in advance.

Don't be jumping 3-wire "switches" they are pressure transducers- that feed exact a/c sensed pressure readings directly to the ECM-- you could fry an ECM that way- if the system has adequate pressure-(47psi) the compressor will run.

Most typical scenario is you have lost a considerable amount of refrigerant- and the pressure transducer has disabled the a/c compressor- so it will not run without lubrication and destroy your compressor. Most likely leak location is compressor shaft seal and/or compressor body o-ring leaks.

What is your system pressure?

Oops. I am planning on buying a self A/C charging kit ie: REDTEK but I need to engage the compressor for it to charge. I can't look for leak until the system is pressurized. Any suggestions? Thanks.

You DON'T need to engage the compressor for it to charge--Your can pressure at room temp (approx 85 psi) will be enough to pressurize the system to above 47 psi then the compressor will come on..

If the system is dead flat (0 psi) then your leak is big and you need to find and fix it and pull an adequate vacuum and then recharge..

I just got one of those self charge kits & one of the options available is running a dye to find a leak.

Not positive about this but don't think you're supposed to mix the new with the usual stuff. So if your air does have a charge but is not working for other reasons, you may have to take out the old refrigerant to put in the new.

I think most air systems have a schrader valve (like for a tire) to expel refrigerant, or at least if you press it for a sec & if nothing comes out then good bet the system is dry.

If you have a leak, you also need to be concerned not only about refrigerant, but the system also needs a small amount of appropriate oil that may have leaked out with the refrigerant. There are kits available to check the oil.

I've used the self charge kits in the past & can confirm that the stuff can go in with the compressor not running & then if the AC system is in order, the compressor will fire up once there is enough gas in there. If the compressor doesn't fire up then something needs to be fixed.

I like the new kits available, they can be had with a gauge that shows you when enuff gas is in the system. Too much (= :nono: ) can break stuff.

If the system leaks down that bad or fast then chances are there may be moisture in the system as well...

On my 95 TS with the HR6 Compressor, I had a pin hole in the condenser... I added a couple of ounces of PAG 150 oil and replaced the inline filter, and seals... I pumped the system down and made sure it held.. It did... I have found that the compressor did have a small leak... It was quite slow, but has seriously picked up its pace... I had also found the the compressor was not developing as much pressure as it should have on the high side... Compressor has been getting worse so i won't even bother with another charge Untill I replace the unit..

The Van will get a Reman Compressor, replacement tube filter again, also a new Drier and I am going to go ahead a tear it down and replace the Evaporator and Heater Core for good measure... After all of that is done"( also with new seals ) I will again make sure the right amount of oil is added, and being that the system was open I will pump it down again to boil off and remove any moisture..

When I pumped the system down and charged it up, the AC system blew very cold even on a 90 degree day and that was sitting still...

Just remember if you do it right the AC will cool you off..

And its agreed, the system will cycle on when a that said pressure is reached... No need to try and force the compressor..

Thanks for all the input. Charged it last night and it worked. Now I can look for leaks.

Sounds like all the old stuff leaked out. If lucky, you may have a small leak & will only only have to top up once in awhile. They have sealers that can be tried out, light & heavy duty. Might help with minor probs.

As mentioned, there is also dye available to find a leak & also a bottle, or a way to figure out the oil situation.

I just had a glance at what is available ..the other day.

~15 psi was left in the system before I charged it. Probably a small leak as you stated. I will look on the weekend. Thanks