I posted this in "C4 Parts", also, but thought I might get more views here.
I need this switch (fits on the rear of ac compressor in my 84).



It must have the metal base, (takes a 9/16" wrench)



I've tried 3 different switches (all brand new) from 3 different manufacturers, supposedly for my 84, but they were all too big. (All 3 had plastic bases)
The threads on mine are small. All of the new ones slid right over the threads on my compressor.

If anyone has one or knows for sure, where to get a new one (the correct size) please let me know.

 

you can get this switch form corvette central or your dealer. It would probley be faster threw your dealer. CC has to order them and the dealer can get them faster. CC part number I think is 454622. This switch does not do what most think it is a high pressure temp switch. It monitors the high side temp and shuts the compressor down to keep the evap form frosting over. Even cc describes this wsitch wrong it is not a clutch cycling switch working off pressures. I do not know of and aftermarket sources for this switch. CC is going to get it threw the GM network I am almost positive. You will do no harm if you want to just cross then connections except that the evap may frost over and you can get some condensation spray out of your vents if this happens. hope this helps. I am saying this based on 87 up to at least 90 vetts. But this appears to be the same switch just not in line like the latter models. It is as far as I know the only switch with the brass base. hope this helps

 

It has nothing to do with frost or the Evaporator Icing over.

That's either the Coolant fan switch or the High Limit cutout which was unique to the '84; should be acdelco #15-2151. They probably keep selling you the Low Pressure Switch which is either on the Evaporator or Accumulator. Are you sure you need this switch? Talk to the guys at www.ackits.com for more info or if you're unsure.

 

like I said if it is the same as 87up on them a very simulator switch is located inline right before the evap. and that is a temp switch that is why I said if the same

 

Positive!

 

Oops - I've done that at one time or another! Try the guys I posted for more info. The '87 isn't the same.

 

that is what happend to the switch I am talking about If it is the I am talking about if you look you should see a thermo contact plate, Like I said I am refering to 87 up till I think at least 90 but it looks like the same switch just different location. I ran into this in 90 or 91 had one come in a the switch was broken just like yours. I call my local jobber told them I needed high side pressure switch got it was wrong. called them back they said that was all they had. They ssaid they did not even show 2 switches next to each other on the evap line. rode down to local Gm dealer pulled up the fich and found it. Gm called it High presuure temp switch. looked in all data and sure enough there it is. I learned something that day. My 88 broke about a year ago C/C has the correct one shown they get it from GM sources like I said but faster if you go directly to dealer. You couls run down to your dealler have them pull up the pictures and see for sure what you need or have

 

Believe me, the '87 doesn't use the same and the '90 is different still. You can figure it out and x-reference at www.acdelco.com but you need to know what to look for. Switch needs a different threshold at the Compressor outlet than you need on the liquid line after the Condensor which is where it is on your '87. Over the Years, GM advanced compressor control to the PCM, added a Thermistor so system performance could be monitored at the CCM, switched compressors and later reversed the manifold and a host of other changes which led to parts that aren't always interchangeable among Vettes, but maybe among Buick, Olds, Caddys, etc.

 

Sun I did not mean to confuse things I tried to be clear that I was not sure the switch I was refering to was the same as on his car. It just resembles the temp switch that as far as I know is used on most 87 thru 90 Gm cars. I do not have the GM part number whit me I no longer work so I cannot look it up unless I swing by the shop. I think you have a 89 if you look at the high prssure line going into the evap you should see 2 switches I cannot recall but I think it is the one closest to the evap. that is refered to the temp switch it is used to moniter line temp so the evap does not freeze up. The only reason why I was thinking it may be the same switch is that GM very seldom uses brass A/C switches. most are molded plastic. also the op said something about the threads and size on the switch I am refering to the threads and size are totlay different than any other GM switch. So my quess is he has already went to his local vendor and they pulled every swwitch for that year. If it is the switch I am refering to it is only adv threw GM and in most casases has to be special ordered.The last one I got I wainted 3 weeks for and that was from a very trusting dealer. I just just the term till it came in. Adain sorry for the confussion I caused you and the PO I really tried to make sure it was clear I was not refering to his car. alls cool!!!!!!

 

I need the same part for my 84. Actually, I don't need the brass part, just the plastic plug part because the plastic has broken on mine and it will not stay connected to the brass part. I went to a chevy dealer close to me and they could not find it, nor give me a part number. If you have any luck, sure would appreciate it if you could let me know. I know exactly what you are going through because I am experiencing the same thing.

 

the plastic part is part of the whole switch. I would think the Dealer should be able to pull up the whole A/C diagram and show you the part. Then again Im sure they are getting rid of their older information. Again you both can go to corvette centrals site and take a look at the switch they offer see if it is what you need their part number 454622 I do not know what years they say this switch fits by hey it may be worth a look

 

Thanks for the replies. I'll check around the dealers Monday.

 

Switches on the High Line - '85 through '89 - are High Limit (opens at 400 psi) and Cooling Fan (opens at 230 psi; recloses at 190 psi). '90 through '91 uses similar though there are now dual fans. '92 uses a Thermistor on the high line with return voltage proportional to pressure. It's used for fan control and diagnostics. All Years use a Low Pressure Switch on the Evaporator outlet to control icing and on '90 through '96 for diagnostics. '84 had the high limit and/or fan control on the Compressor. Low Pressure Switches have the threshold set for R12 at 25 psi; for R134 at 22.5 psi. Be sure to specify what gas you're using, though some are adjustable.