mobius

long story short i replaced the ac compressor in the car the new one was bad and locked up. after replacing it the clutch would not lock up. found a 14 amp fuse blown replaced it but still do not have power on the plug going to the clutch. does somebody have some suggestions or a schematic so i can troubleshoot

thankyou

gwj

Yeah, I've been through that scenario in the past of having a new/rebuilt compressor lock up once the clutch was engaged.
As for the clutch not locking up after being replaced, are you sure there is enough freon in the system? At a low pressure, I -believe- the clutch will not lock up to engage the compressor.
Also make sure the pulley on the compressor is freewheeling when you turn the AC on. Sometimes a new/rebuilt compressor just don't work (always turn one over by hand before you install it).
Good luck.

Stu

You can always just put a jumper wire in the pressure switch plug.

But what gwj said. You need the right amount of freon in the system to turn the clutch on.

mobius

ok i put a jumper on the press plug and the high speed fans come on but the compressor doesnt move. there is a black shrink tube connecting the red and green wires that go to the clutch, any ideas what it is, a surge suppressor or something? if i check the plug i get .5 ohms which to me means shorted but i think that thing connecting the wires may be causing it. anyways the fuse isnt blowing anymore but the compressor will not engage and there is no voltage on the plug. what about running wires from the battery to the clutch just to see if it locks up?
thanks for any help

mobius

anybody???

trackbird

iTrader: (4)

DO you see voltage on the system? I've not dug up a wiring diagram yet, but I'm wondering about a bad fusible link somewhere along the way. Just thinking out loud, if I get a chance to look at the wiring diagrams, I'll post what I find....

mobius

trackbird if you could look at a schematic that would be great. i have isolated the problem to the ground on the control side of the relay for the compressor. i can jump out the secondary side and get power to the clutch and i have power on the primary side but i do not have the ground to complete the circuit. i believe there is a safety or pressure switch or something holding the ground out. could you please check the schematic and let me know.

Thank You

canadian z28

try jumping the connector at the low pressure switch usually found on the accumulator. Put a cotter pin in the connector so you fool the system into thinking it is activated and the compressor should come on engaging the clutch. If you have no freon in the system, it will still turn on. If it comes on, replace the low pressure switch. But like everyone said, make sure you have enuff freon in the system as well. Simply putting a swithch in without enuff freon will not make the system work.

mobius

ok i think i have two problems maybe they are related. first is clutch will not engage i.e. relay will not close. i tried jumping pressure switch and it didnt help. what is and where is the evap temp sensor?

second problem i jumped the relay and blew the fuse. so either clutch is bad or the diode or whatever that thing is in line with it is bad. how do i check it?

thanks

wrencher

iTrader: (2)

The evaporator core tempurture sensor is outside the hvac case under dash behinh glove box.
The diode should have continuity one way + to - .
Diode should alow current to flow in one direction only, it's an electrical one way check valve. With out it the relay would be subjected to 300 + volt spikes every time it turned the clutch off. The diode bleeds this spike to the ground side of the clutch circuit.
The PCM turns your relay on , do you have A-tap or something you can check the data stream with ?
Make sure it has an A/C demand & no high P/S demand & that the high press swich is not shorted.

mobius

thanx man i have autotap can you explain in more detail what i should look for. if i jump out the high pressure switch the high speed fans come on so i believe it is working. not sure of the evap sensor.

thanks

wrencher

iTrader: (2)

See how many A/C pid's you can get , a/c demand yes/no, a/c clutch yes/no, p/s hi press. yes /no.
These might help steer ya in the right direction.
The compressor does run if jumped out thru relay correct??
+ the system is full or refrigerant?

mobius

ok founf one problem the diode in the harness was shorted replaced it and now i can pull the clutch in by jumping the relay but he relay does not close on its own. i tried jumping the pressure switch high speed fans but no clutch. there is no freon in the system as i couldnt charge it with out the clutch engaged, right?

wrencher

iTrader: (2)

You can get maybe a pound in & use the compressor to pull the rest in.

Cal

iTrader: (1)

If the system is totally empty, it will take two cans to refill it. I think each can is a little under a pound. If it blew down fast you may need to add a little oil as well.

mobius

ok think i got it i am going to charge it tonight or tommorrow, friend coming over with gauges. how many pounds should it hold?
fyi after replacing the diode it appears it set a couple codes and would not engage the compressor until they were cleared.
ill keep you updated
thanks for the help

mobius

ok i am in disagreement with my buddy that is helping me, we put 4-12oz cans in and i think that is to much, he says its not. i believe two is all we need. can someone tell me the correct answer.

it is not cold just cool but working. i checked the vents they appear to work and i cannot feel any air running thru the heater core, that was a concern we had....

2xLS1

iTrader: (25)

Total capacity is 24 oz. (2) 12 oz cans. There is a label on the stock air lid that lists the capacity.

mobius

cool thanks, i have 48 in it now.... time to purge.... i found it on a site as well... i guess i will have to find my stock lid to find the sticker thanks