A/C High Pressure Switch

Not at the moment, no, I can't. But I can when I get back in later this week then I'll know for sure.

 

Leaky fan clutch was my culprit and now I have the Rube Goldberg'd a/c high press switch wire harness correctly hooked up like it is supposed to be. But I don't think my troubles are entirely over. The engine fan does not seem to want to kick on automatically when the truck is idling and the a/c is on like it is supposed to. Now the outside ambient temp is 54* and it is raining but I am thinking it should still kick on ocassionally when the pressure gets up. But it wouldn't do it after 5 minutes idling on several attempts. Dang it.. fix one thing and something else still not quiet right.. #### trucks.. I'll just run it like this til summer and deal with it later, using the fan manually when parked with the a/c on, like I have been doing forever anyways..

 

Glad you found that leak. Did you do the whole kit? Any problems on the way? Was the nut hard to break loose? lol. Can you attach high and low gauges from an a/c manifold and see what your psi's are? I'm thinking you already did that and the pressures were right on. Just wondering if you are actually getting up to the psi you need to be to kick it on.

Oh yeah. I see you have an 03. What kind of milage are you getting with your upgrades and what weights are you pulling when getting them? Thinking of sending some of ours to Kurt for the brakesaver. We have quite a few of those engines.

 

I had it installed so I don't even know lol. As far as what pressures with gauges hooked up, the last time we were trying to figure this one out, and the switch was somewhat working the fan kicked on at the right amount of press. But I cant remember what it was.

Summer blends pulling heavy loads 78,000-80,000 I'd avg 5.8 mpg with very little to zero idle time running around 68mph mostly through the I-81 corridor in VA. That was at the old company. Now that I'm pulling mostly lighter loads I'm easily getting 6.0 to 6.5 mpg. I've slowed down since then also and run 65mph pretty much everywhere unless the posted speed is slower. This is pulling a dry box.

210,000 miles on the ECM flash, turbo upgrade, and fuel temp wire all done at the same time after the original turbo was toasted (exhaust housing had hairline cracks and I couldnt get boost over 20psi). The truck had never been better before those upgrades. Pyro temps went way down, water temps too. With stock MBN flash files I could easily see 1100* on the pyro, maybe more but I would always let off the go pedal when it got that high. I was constantly running the engine fan to keep it cool when heavy in the summer time too.

Now my pyro temps never go over 825*, never... Turbo will build boost up to about 36 psi or so now. Still use the fan with heavy loads in the summer but not near as much. Engine runs much cooler and power is up substantially. Picked up about 3 tenths of a mpg on the upgrades. Well worth the money. I had $2,700 or $2,800 in those 3 upgrads and that was doing the labor myself. It cost over $3,000 now to DIY with price increases. You won't get the turbo for what I paid for it and Haney has gone up $300 on CAT flashes since then.

 

Please help me my A/c works great for about 5 mins than it stops cooling I replaced the high and low pressure sensors but that didn't help the clutch disengages and doesn't engage till hours later or it feels like it.

 

Check the thermostat in the heater ac box. You can bypass it for diagnosis, use a short jumper with 2 male spade connectors.

 

Thank you for your advice but we found the faulty piece it was the expansion valve.

 

1995 w9 replaced everything from expansion valve to back of sleeper. A/c compressor doesn't cycle low or fully charged.stays runninganytime a/c or defroster is on.is this because of high pressure switch?

 

When dealing with the Ac it is very tricky because the pressure deals with almost every part. There's video on you tube that shows you how to check the ohms on pressure switches and it works. So it comes down to freon in the line which creates pressure ( too little or too much which causes compressor to react)or the the expansion valve.