Mitsubishi: 94 mirage 1.5 AC Comp not starting

"LWG" <com> wrote in message
news:com... 

Look at the relays just behind the LHS headlight. The harness connections
can get corroded.
Check that the belt that drives the compressor is not loose.

Most likely however the system has depressurised. There's two (tire type)
valves: Low pressure, on the tube/hose near the firewall, and high, on the
tube just in front of the power steering pump. Unscrew the high pressure
cap, and press the valve MOMENTARILY. If you get a loud high pressure
release, the system is pressurised. If you get a quiet hiss or no sound at
all, the system is low or depressurised, which is why the AC does not work.

Partial depressurisation occurs when AC hose O-rings have deteriorated, and
should be replaced. Often happens during winter. Full depressurisation
occurs when you have a corrosion hole leak.

An AC shop can do a vacuum test to see if there's any leaks. If the system
still has some pressure, you may get by with a simple repressurise. Just be
aware that it will leak away again in a few months. Cost is about us$160.

If there's no pressure, then you need to find which part has the hole. An AC
shop can easily identify a hole. Its most commonly the condensor in front of
the radiator, but the two hoses can be problems too. Check for prices of
these parts from a wrecker (93-95 parts are all the same) then check the new
price. ($$$$$$)

If its just the O-rings on the hose ends, then the AC shop needs to
a) R/R the hoses and replace the O-rings
b) replace the drier cannister (mandatory) next to the LHS strut tower.
c) vacuum and repressurize.
Should cost in the order of us$250.

It MIGHT be the compressor. If the AC shop says this is broken, get one from
a wrecker. I have one here from a 94, in perfectly workable condition (came
out of a working system).

Stewart DIBBS, Ottawa, Canada
www.vysor.com/lancerproject

Stew, I bought a small AC recharge device and connected it. The guage
on this device indicated I was full, so I did not recharge it. Do you
know of a relay involved in this? It is looking like either the
compress clutch(maybe) or something is not turning it on. I did
connect a volt meter to the wire going to the compressor and turned it
on and got no voltage. Any thoughts?

thx, L

On Sun, 03 Apr 2005 09:01:38 -0400, LWG <com> wrote:
 

"LWG" <com> wrote in message
news:com... 

OK, you sound like you use tools, and I just happen to have my circuit
diagram handly.

On the top of the drier canister is a triple pressure switch. If the AC
pressure is within spec, this switch is closed. Pull the connector and check
with your meter. If its open, the compressor clutch won't engage. You can't
replace the switch without depressurizing the system, but you can just jump
the wires if necessary. There should be +5V (from the ECU) on one of the
switch wires.

There's another temperature switch on the compressor itself, and opens if
the gas temp gets too high, disengaging the compressor clutch. I've never
seen one fail.

There's a relay (the first relay behind the LH headlight, next top the inner
guard) for the compressor clutch, and a 10A fuse that appears to be in the
panel under the dash, to the left of the brake pedal. The relay group gets
all sorts of water on it and the connections corrode. Pull the assembly out
and check.

You can test the compressor clutch by undoing the connector in the cable
that comes of the compressor, and applying +12V directly to the RED-BLACK
wire (other is ground). If the clutch is OK you'l hear it click, and if the
engine is idling, it should slow down.

regards,
Stewart DIBBS
www.vysor.com/lancerproject

and also
========================================
Developer of the PiXCL Image Processing and
Analysis Language for Windows 2000/XP
PiXCL 6.0 is available now !
www.vysor.com Gatineau, Quebec, CANADA

========================================

Stew, I was having trouble finding some of the things you mentioned.
However, I beleive we fixed it. I was checking fuses and found nothing
labeled AC, no fuses blown btw. I also removed connectors etc. and
reseated them and the compressor kicked on. Keep an eye on this thread
I will be sending a picture of the car engine bay. When you get a
moment could you point out some of the different AC subsystems drier
etc.? I have the base line model car, I believe AC is the only option
on this guy. Nothing special, but good gas mileage. Also, the relay
you mentioned seems to be up in front of the radiator/condensor to the
left (drivers side) head light?

I wanted to say I appreciate your update (to the thread) and patience.

Lessons learned, reseat all connectors first.

thx again,

Larry

On Wed, 6 Apr 2005 18:00:41 -0400, "Stewart DIBBS" <com>
wrote:
 

Some pictures of the engine. The sensor I reseated and appearently
fixed the problem is in one of the pictures and the other contains the
compressor and only has one wire running to it. That must be the 12v?

On Sun, 03 Apr 2005 09:01:38 -0400, LWG <com> wrote: