A/C Doesn't Work

[87-F-250]

I'm not getting any power to my A/C compressor clutch. When I press the button inside the cab it turns blue but when I put a test light on either wire nothing.

P.S. I just posted some information on the 2011 IDI Weekend

http://blogs.dieselpowermag.com/6676091/diesel-engines/2011-idi-weekend/index.html

 

[93f250idi]

if its like my mustang theres a switch on top of the a/c dryer. unplug that switch and theres two metal holes inside the plug. take a small piece of wire and wire those two holes together. all this is doing is hot wiring the switch. if your compressor kicks on then thats your problem! just dont leave it hot wired or it will build up too much pressure.

 

[subway]

the switch can keep your system from running if the charge is to low. if the charge is to low there is not enough lubrication for the pump.

 

[timothyr1014]

that is the low pressure switch...if this trick works you either have a bad pressure switch, or are low on refrigerant.

As stated above, this switch cuts the system off if there is not enough pressure to circulate the oil which would burn up the compressor.

The "perminatly jumping it builds up too much pressure switch" is called a high pressure switch...being that the 87 was originally an R12 system I highly doubt it has one of these unless it was added when doing an R134a conversion.

 

[Dirtleg]

As mentioned above that is the low pressure switch. Put a gauge on your A/C system and see if you have over 25lbs psi on the low side. If you do, jump over the switch connector and see if the clutch pulls in. If so your switch may be bad. It has a screw inside the connector base that allows you to adjust the trip pressure. If the switch is actually bad you can change it without loosing the refrigerant.

Most likely you are low on refrigerant and the low pressure switch it just doing it's job and protecting the compressor.

Best of luck.

 

[Simp5782]

Also check the a/c high pressure cut off switch. I have had several go bad and they will cause it not to kick on as well.

 

[87-F-250]

I just got back from a few different shops. At the first shop I went to we tested the system with compressed air and it held 60 psi for 20 minutes. He said he wouldn't be able to do anymore that day. He said since I had the old R12 he would need to pump it out and then flush the system by unscrewing the hoses and getting all of the old out because it doesn't mix with the new. He said it would cost $200. - I paid $35 for the testing.

At the second shop they said I would definitely need to replace the whole system including lines, compressor, dryer, condenser to accept the R134. They said it would be better to get a new truck $1600.

The last shop I went to they said I should probably replace everything but don't necessarily need to. We just added an adapter to the high and low side ports and then pumped out the R12 (maybe it had been done before?) and put 3 pounds of the new oil in. It blows cold now but will it last? cost $140

 

[Dirtleg]

Well based on your explanations shop 1 was probably on the right track. That doesn't mean you'll have problems due to shop 3 but it is always best to clean the system out when changing refrigerant. Plus 134 uses a different oil than r12. Shop 2 really didn't want any of your business IMO.

So what was the system low pressure before you evacuated it? Curious is all.

 

[87-F-250]

0 psi it had been sitting for 3 years or more?

 

[93f250idi]

put a can of oil in it then fill it up with r134 you dont have to spend no 1600 i did it to my truck does fine

 

[subway]

it is good to replace the drier especially if it has been sitting but you should be fine a long as they flushed it. good deal!

 

[Simp5782]

Yeah, buy some a/c line flush, unhook all ur lines, receiver dryer, and evaporator. flush em out good with the solvent and an air blower on a compressor. Install ALL new orings on your lines. Carquest bout 20$ for the whole big kit of orings. The solvent will not hurt the a/c system if u dont get it all out. It will dissipate. If you have the 134 adapters u can skip the next step. Personally i prefer a dual gauge system to monitor the high side instead of just charging. You will need to add 7oz of pag 46 oil to the compressor/lines wherever u wanna put it. MAKE SURE YOU FLUSH THE COMPRESSOR. Dont forget that big piece, alot of the old grime and gunk likes to sit in there. I will advise you to replace your orifice tube. It just helps get it a little colder and they tend to clog on ocassion. Charge the system with 2lb 3 oz of freon. round bout 2 1/4-2 1/2 cans. I would recommend placing a big fan infront of your truck while charging, It just helps with the high pressure on the condenser.

Overall
Solvent/Flush $12
Orifice Tube $2
Pag oil $7
Freon (its up to you. I would prefer the R134 with stop leak)
O ring Kit $20. Unless u wanna match all the orings up individually. Its up to u.

So round $60 you will be good as new. Cheaper than buying R12 at like 60$ a lb

 

[Diesel JD]

Only time will tell. I'm hoping it works out great for you.

 

[timothyr1014]

I agree with above....see how long it lasts....but to be honest, the "replace everything" approach is usually done for 1 of 2 reasons
1. they dont want your business, so if you choose to stay they get to take your wallet
2. they are worried about what there walking into and want to know they have the budget to cover it.

Either way, to be honest there are lots of us here who know AC systems and can give you advice on how to get it all working for WAY less then your $1600 quote

 

[Simp5782]

Well you can always do the old fashion a/c when your driving, the 60 at 60 window