86 is ignition power. 30 is battery power. (some cars it is also ignition power) and 87 goes to the clutch.
What year is your truck?

 

It's a 2003. I made sure the wire going to the compressor isn't broke. I have constant battery power. Would have the check the ignition power again can't remember. I mean I'm at a loss with this one

 

Here:

 

That is what I was looking for where did you find it?

 

I have certain perks.

 

Man thank you so much that helps. But it also doesn't make sense as to why I don't have power to the low pressure switch.
But thank you so much.

 

It's not like the older cars, It doesn't work off of power. Jumpering across will eliminate it from the equation.

 

subscribed

 

I've tried jumping it and replacing the switch still does not turn the ac on. Guess I'll just take it to someone and have them figure it out. I have done all I can without a scanner.

 

Keep us posted, have buddy with exact same problem in a 2003. I've tried everything you have and still haven't gotten anywhere.

 

You guys are basically throwing parts at something that can be complicated, especially if your truck(s) have auto a/c. There are multiple temp sensors in the cabin (5 iirc) and one behind the right side headlight. Both auto and manual systems are known to have the a/c control head or high pressure switch go bad, along with the other things talked about previously.
It may actually be cheaper to have someone scan it.....all you need is a code to work with, most of the time. If money is tight, pay the 70-100 buck diagnostic fee, then take it home and fix it yourself if it's something you can do....it's a bit risky that way, but can potentially save a good amount.

To sum it up, a/c is probably one of just a few systems in a vehicle, that really should be handle by a pro. And please, to anyone that may come across this post, DO NOT ADD SEALANT TO YOUR A/C SYSTEM....yeah, those charge kits they advertise on tv, they can really mess up our a/c equipment. If a shop knows you added sealant, they may refuse to work on your vehicle (I refuse outright), not to mention overcharging the system by mearly a few ounces can have a terrible affect on the system, possibly damaging the compressor.

Rant over

 

Yeah I've tried cheap stuff kens auto so I guess now I'll just try to find time to get it in the shop.

 

I've used the cheap crap from the hardware store before, but I used it on $200 beater work cars that I wasn't gonna take to a shop...why spend money on the "disposable" cars.....haha

 

No i meant the cheap stuff as like the low pressure switch was like 10 bucks plus tax and a few other little tricks. Haven't spent big money on expensive parts

 

Ok now I'm fed up. I took my truck to the dealer to get checked out. Told me it was the compressor and my ac still doesn't work. and magically now my blower motor will not change speed...... Not real sure how to go about testing it. I have power going to it and the ground is good.
Power goes to the blower motor but I'm starting to think it's the control unit for the hvac. Anyway I can test it?

 

I know this is an old thread but did anyone figure out what the problem was my clutch wont engage either and have tried everything but a scanner so far. Can efi scan tool be used to help diagnose?

Thanks

 

Hey Willie, what a day for A/C, eh? My 2004 is doing the same thing, let me know if you get yours sorted, I just posted a new thread on it.