Not Advanced by any means... moving to Help Tech.

 

Respectfully to the moderator who moved this from advanced; I read the rules of advanced posts. Where will you find this problem in the 1000Q F.A.Q.? Where will you find this problem/solution in a Haynes or Factory Service manual? I have both. Where will you find this problem answered on this site? I did a search. I went through every post (ALOT) that had he word FAN ! in them..along with other obvious keywords. Maybe you know the keywords that will give results. I tried everything I could think of. Also, this is not "Topics like how do I do XXX maintenance/service are a prime example. If you get stuck in the middle of something, you should post in the Help forum."
If this isn't a question for DSM Guru's, for those who are "advanced" in knowledge, why can't I find an answer on this Site, or a couple of other Dsm sites. I checked my coolant level. I swapped out the entire fan with another that works. I have not been lazy researching this problem.

Anyway... help.

 

By the way, I have also tried the mod in the V-Faq that turns on both fans all of the time. It has no affect on my AC fan.

 

Hi,

Thanks for asking, I see you at least *read* the rules unlike some people... Advanced is designed for topics that have not been discussed ANYWHERE else (specifically the Talon Digest, 1000q's, here in the archives, etc.). Honestly, your problem does not fit into this category.

I understand how it can be frustrating to have a problem and not get any answers to it. May I suggest that the problem is not with the fan but your electrical connections to it? You already tried swapping the fan (good call) but that didn't work. So logic would suggest that the switch/relay/wiring is the next problem. After that I would suspect either the switch in the cockpit isn't working or there is an ECU-related problem (harder to detect).

Have you tried the archive search on DSM.org ? It searches thru the Talon Digests of the past 10 years or so... you have to use the one where it says new archive searcher --> http://207.154.72.181/

BTW, I don't always see follow-ups to posts so you can always PM/email me directly and I will see it for sure.

I hope this helps you a little bit and doesn't discourage you from trying to ask for help and visit here...

 

No, I'm not discouraged. Your reply and advice above was very helpful. Thanks!
What my tests and research now suggest... is that there are two probable sources for this problem. I tested every fuse in the car, and checked the talon digest archives. There is something called the AC Amplifier, somewhere behind the glove box, that controls the air conditioning system. (including the ac fan) If the AC amplifier is faulty, the AC Fan will not work properly. Incidentally, what also led me to this conclusion is that my AC compressor will not come on. When all the wires and fuses test correctly, Failure of the fan and the compressor suggest the AC amplifier...or worse, perhapse the Car's main ECU as the culprits. ~please no~

Anyway, a friend of mine has tossed his entire air conditioning system to make a "race car".. so I can probably use his AC amplifier to test my theory.



cooling fan, wont turn, AC, fans, air conditioning, compressor

 

Excellent! It seems like you're on the right track - keep us informed!

 

There is a fuse for the A/C fan located in the driver's side underhood fuse box. If that isn't the problem then Its more than likely you are low on freon. There is a pressure switch in series with the condenser fan motor relay holding coil. This keeps the compressor clutch from engaging if the refrigerant charge is low. Freon cools the compressor so low freon would allow it to overheat should it run.

There's how the system works. If you turn on the A/C and the A/C controller is calling for cooling the controller energizes the condenser fan motor relay coil, closing the contacts and causes the magnetic clutch on the condenser to engage. There is another relay called the high-low change over relay that has contacts in this circuit. If the radiator thermo sensor is not calling for cooling the high-low relay is in low and both fans are powered off the low side of the resistor pack on the A/C fan and run at low speed due to the resistors. If the radiator thermo sensor is calling for cooling then it's contacts close and energize the high-low relay coil, move the contacts to high and the radiator fan is disconnected from the A/C fan. The radiator fan now is powered by the radiator fan relay (also energized by the thermo sensor) and the A/C fan is powered by the condenser fan motor relay. The resistor pack is bypassed and both fans run at high speed.

When the radiator thermo sensor contacts open the radiator fan motor relay contacts open and the high-low relay contacts switch to low. Well, it seems the high-low relay contacts always switch before the radiator fan motor relay contacts open allowing a little shot of DC gets through to the A/C fan causing it to momentarily run. All 1G DSM's I've had my hands on do this.

 

On my 91 AWD the drivers radiator fan comes on when you push the dashboard A/C button even with the AC compressor relay pulled (obviously it doesn't come on with the fan relay pulled) so I don't see how low freon would effect the radiator fan function - just the compressor function. I think the low freon switch is in series with the compressor clutch relay - not the radiator fan relay. There is a resistor behind the glove box that controls the internal condenser fan speeds & POSSIBLY the radiator fan speeds if I have read the manual correctly they have 2 speeds. IMO you'll drive yourself nuts troubleshooting this w/out a manual. There are switches, relays, resistors & fuses & thermo switches all over the damn place. BTW - when my big passenger side fan kicks OFF the drivers side fan moves for just a second - I THOUGHT - that it was just a sympathetic reaction due to air flow change or something - I don't THINK that the drivers fan is seeing any electric pulse making it move for just a second & I THINK that's all you are seeing - granted it should run when you push the AC button. It appears that several of the relays have the same part number so you can swap them out to different locations to verify operability if you don't have a meter to read them with. They are not cheap, good luck.

 

Yeah, by bad, there is a separate relay for the compressor clutch and the high/low pressure switch is in this circuit.

Both fans are fed off the resistor pack on the A/C fan for low speed. The resistor pack under the dash is for the heater fan only.

As for why the A/C fan spins, the point is that it is not diagnostic for anything as they all do it.

 

Yeah, my bad, there is a separate relay for the compressor clutch and the high/low pressure switch is in this circuit.
Both fans are fed off the resistor pack on the A/C fan for low speed. The resistor pack under the dash is for the heater fan only.

I just had an air conditioner technician look at the car. He checked my Freon. It was good. He is not a DSM specialist, but he also suggested that the AC amplifier (located in the glove box near the evaporator) is the culprit. I didn't really learn anything new from him. But..........

Are you saying that probably isn't true? Does the AC amplifier explanation sound possible to you? I read that it controls all the air conditioning functions...and it can go bad.

The reason I ask, is because I'm about to try and find this AC amplifier on a parts car that I know had working ac, and replace mine with that one...

but I don't want to do that if Its a huge waste of time.
Any input?

Cliff notes: Freon is Good Fuses are tested and good. Is there such a thing as an AC amplifier (suggested by ac technician) near my evaporator?

 

Yeah, its got one. The Mitsu folks call it the A/C controller and it certainly could be the culprit. I made other suggestions because it is unusual for the controller to fail and I wanted you to check the more common problems first. But shit, these cars are getting old. So anything is possible.

 

I had another guy with the same problem and the fuses were fine. Well, I told him to pull the fuses in the driver's side box and put an ohm meter across them each. Guess what, even though both fuses looked fine one was open.

So, if the technician didn't do this, give it a try.

 

Well then, I going to swap out "AC controllers" and see what happens. If that doesn't do it... Then it was suggested that my car's main ECU could be going out. ~groan~ Hope not.

 

.

check your high pressure cut out switch and the low pressure cut out switch the passenger side fan is only supposed to come on when the A/C button is pushed ON. (green light on) the low pressure one is on the reciever/drier right in front of the driver's head light and the high pressure is on the back of the compressor at least that's the way it is on the 2g so...hope this helps man.

Thomas BTW where in memphis are you from? im from c'ville.

 

Hey Thomas, I live near Kirby and Winchester (not to far from the Best Buy store on Winchest. But, we're moving out to Hacks cross in a few weeks. I know two other guys with turbo dsms around here. We might meet up sometime.
Anyway, for 1G DSM's Barney said it is normal for the AC fan to kick on for just a second. But, I do need it to run when it should..and it isn't so far.
When Barney said the following.. I had another guy with the same problem and the fuses were fine. Well, I told him to pull the fuses in the driver's side box and put an ohm meter across them each. Guess what, even though both fuses looked fine one was open.
So, if the technician didn't do this, give it a try.
I thought, Hey, maybe I should double check things before I swap AC controllers. So, the double check is my next step. THEN, the ac controller.

 

Update and Solution (1g 1992 turbo car with AC)
and Thanks for all the input guys!

Symptoms and Processes of elimination:

1. Air conditioner does not blow cold.

2. Air conditioning Fan (driver's side fan) will not come on when air conditioner button is engaged.

3. Air conditioning Compressor does not activate when air conditioner button is engaged.

4. All fuses in the car are good. All relays are good. Freon level has been checked. Coolant level has been checked.

Solution

The Air conditioning Controller was my problem. I was told that it controls nearly all functions of our AC. It is a small box, about 3 inches long, and an inch high, that rests behind your glove box. One screw holds it in place. One connector full of wires plugs into it. To get it out, lay your passenger's side seat all the way back. Then lay down in your car either on your back or stomach and remove the glove box. (There is a plastic grommet on each side of your glove box. Push down on them, and they will pop off and pull inward into the glove box, allowing the glove box to fall completely open.) On your back, you can then see the ac controller. The single screw can be removed with a VERY short phillips head screwdriver, but I had to resort to a small socket wrench, using a 7mm socket. That is the easiest way to get that little screw out. Then , after unplugging the wire connector (there is only one) just wiggle the ac controller out. Replace it with the one you brought with you.
My AC had not blown cold since last winter. I thought it was low freon. After this replacement, I cranked up the car and had ice cold air...and a working AC Fan.

I hope this helps anyone who experiences the same problem.
I'm told that it is a RARE problem, but... there ya go. It happens.

 

Great followup!

Now that's what I call a followup. Great info, you guys.

SleepR DSM, I have the exact problem with my AC. I think I should just order "AC controller" (I found out it is $150). That's pretty pricy.

Do you guys think I can rule out other causes such as a bad sensor or connection if my car is doing exactly the same thing?

I hit AC button, it lit up. No AC fan, No AC clutch engaging. Just passenger side fan coming on. When I turn AC off by pressing AC button again, driver's side fan comes on for a sec.

I am guessing this means all the sensors are working and there is no cut wire. I'm just worried little bit since the previous owner's friend at the Wrightouch messed with the car too much. I mean like the whole wiring.

Anyway, what do you guys think?

 

Does the car idle up when you press the A/C button. I read somewhere that is a good test for the A/C controller.

 

Well, the way I see it...

The A.C. controller was actually easy to replace so
you might try that first and see if it fixes the problem, because diagnosing whatever else it might be, could be more pain than it is worth.

Also, try pulling an AC controller off of a junk yard car. 150 bucks is pricey. I was lucky to have a friend's car to pull one out of. If you can't do that... at least find a place that will let you take the controller back if it doesn't solve the problem.

But, If the symptoms are exactly the same, the A.C. controller will probably fix your problem.

 

Fixed, almost.

Thank you guys all. Especially SleepR DSM and barney.

After checking all the sensors and wiring for about 3 hours, I had a chance to try out my neighbor's "Air Conditioner Control Unit" and guess what? Clutch engages and the fan comes on. Bingo! Since I only have enough pressure in the system to trigger the pressure sensor, it didn't blow cold air yet but that's almost fixed, I'd say.

I should have the new unit sometime next week and I'll get the system recharged. Hopefully, nothing else would fail on me.

 

check your part number for the controller, if it is the same as on the galant, and it probably is, MB276780, sugg list price is only 69.63. i bought one of these 3 years ago, and although it was not the problem, at that time, the price was like 25 bucks. if you are paying 150 for this same part number, i suggest you go elsewhere for your parts. again, i suggest everyone use www.mitsuparts.cc to check out pricing, this allows you to search the ENTIRE mitsu database and get a list price, and a cost price, with discount. other places like tallahassee will ONLY give you pricing on what they stock, and you have to call or email them for what is not in stock. if you pay too much for a part, it is YOUR fault.

 

What?
I tried to check the part number @ www.mitsuparts.cc but I got "The domain MITSUPARTS.CC is not currently registered".

The price ($150) was from Daytona Mits. dealder but I ordered it from somewhere else where I know a guy and I paid $101 for it.

Thanks for the info. I'm definately gonna check if it's the same one or not. Is MB276780 located on the evaporator? A Denso unit?

 

It's mitsuparts.com

 

sorry about that. i have it bookmarked, and the url is mitsuparts.cc. however, it is by far the best site i have seen, because it allows the entire database to be searched.

 

Huh?

I got this.
"Mitsubishi Digital Electronics America, Inc"

Is this correct site???