I believe this happened a long time ago to a Volvo I had, but that was 20+ yrs ago...Since yesterday, the A/C is working fine, but all of the sudden the front blower stops working. The rest of the A/C system keeps working properly, as the rear A/C unit keeps working and blowing normally. With our temps there is no way you can cool the whole SUV without the front unit blowing.

As additional info, yesterday, when it first did it, after 3-4 minutes the front blower started to work again. Today, after 2 hrs of driving it stopped working again, and 30 mins after it was still not blowing. I arrived home, so I couldn't wait more time to see if it would start working by itself. I will wait a couple of hours for the SUV to cool down, and see if when I start it again the front A/C blower works normally immediately after starting the SUV.

If someone has had this issue and knows what the problem is and how to solve, advise...Thanks!

 

Does the blower fan works on High setting? If it does, you have a failed blower motor resistor. If not, you have a motor that is quitting.

 

Hunter, thanks for your reply, always very helpful... It works on High, when it works, it works at any speed setting, and it is even controlled properly on Auto Mode. Leaning towards a failing relay, as it didn't work for a couple of days, then it started working, then it quit, now it has been 1.5 days working properly. For awhile I have been noticing that the AC's cooling performance was gradually diminishing, specially when fully stopped. Checked gas charge this morning and it is on the LOW side (halfway between empty and optimum charge). I will recharge, and see if this fixes the problem with the blower, though I doubt it, as the blower works as a fan with or without charge. Relay is $11.00 at Autozone, so I will replace anyways. I placed my hand over it, and turned the key on and off, at first no "clicks", but after 3-4 times the relay would start to click. For $11.00 it is cheaper than my time to take it out, test it with my multimeter, etc., specially when AZ is only 4 minutes from my home, Advanced is 5 minutes, and Pep Boys about 8 minutes.

 

I recharged the AC system, and purchased the relay, now if I can only unplug the OEM relay, which seems to be welded to the fuse panel!!!

 

According to the repair manual, the relay is located on the inside/cabin fuse panel, and is the first one down to the left. I took out that relay, and it is a 20A 4 legs relay, which I changed with an equal. But, at Autozone, and other places, the relay is a 30A 5-Legs Relay, something is not adding up. Can someone clarify?

 

This gets more interesting by the minute...

First, I confirmed with the wiring diagram that the relay Autozone has listed for my 2005 Monterto Ltd as being for the front blower motor, is not. The correct one is the one with 4-Legs rated at 20A. But, the icing on the cake is the Blower Motor Resistor, the USA Monteros, which mine is, uses a resistor with a square connector, 4-Pins (placed like the 4 dots for the #4 on a dice). That is the one that everyone sells. My Montero has installed from the factory the European one used on Shogun/Pajero. It is a sealed unit with only the fin coil exposed and the 4-Pins are in a row. The std. one used in USA models is only $22.40 at Advanced using a 20% off coupon. The european one my USA model Montero has it's not in stock at any local Auto Parts, so I don't know the price, but I can tell you the 01-03 Toyota Prius uses the same, but with a 90 Deg. female connector, instead of 180 Deg. like mine, and the price is around $130.00.

I see that Advanced carries the pigtail with the square male connector for $32.00 with the discount applied. So, I guess I will have to buy the pigtail, as to convert the darn resistor to the "proper one". A simple $22.00 part is now costing $54.00. Still much quicker and cheaper than the european model (Denso P/N 499300-2110).

This is the second time that something like this has happened to me with my Montero. There was a part that was used in all their 4x4 models, the vacuum selector/valve, that is also used on the Montero. It has a different part number for each vehicle model, and of course a different price, the Montero being the most expensive. I bought it as if for one of their pick-up trucks and saved like 40%.

I guess Mitsubishi engineers mantra is: "Why make it easy, if we can make it difficult"!


RESISTOR CHECK: Use an ohmmeter to measure the resistance between the ter-minals. Check that the measured value is at the standard value.

MEASUREMENT TERMINAL/STANDARD VALUE Ω
Between terminals 2 and 3 (LO) 2.79
Between terminals 1 and 2 (ML) 1.49
Between terminals 2 and 4 (MH) 0.36

This is the one shown on the repair manual and on every parts book there is:



This is the one mine has installed and that cannot be found in the USA:

 

If I was in your situation, I'd try to make a pigtail connector to use with common US style resistor. Another option is to keep looking and see if you can find a parts dealer outside US who may have European style resistor and will be willing to ship it to you.
I can tell you one thing - don't think that Autozone and other stores have correct info for your vehicle. They've sold me 2 different radiator caps that did not fit (i had to get correct one from the dealer). Also, none of their belt diagrams ever looks right ether.

 

Yes, thought about it. The pigtail is available from Advance Auto Parts, so is the regular resistor. But, I was in wrong, the part is not available from Tom, Dick, and Harry (PB, Advance, Autozone, NAPA, etc.). There is no "generic" replacement, only the original DENSO part is available, and only from Mitsubishi parts dealers.

Mine is a Limited with the Automatic Climate Control System. What that means is very simple; everything is expensive. The resistor is for the blower of manual A/C models, basically you control by turning *****. Simplicity at it's best. For the Manual A/C, you have your standard ventilation ****, cool/heat control, and 4-Position blower speed (low/mid-low/mid-high/high).

For the Automatic Climate Control System, AKA the expensive parts model, used on some Montero Limited models and Montero XLS, there is no resistor for the blower. The ***** are there for the feel, as it is an electronic panel with the ***** and a cabin temperature sensor. From that panel, there is an 18 pin Flexible Flat Cable that connects to the A/C's ECU. The A/C ECU sends signals to the damper control, ventilation adjustments, and to an electronic controller that has fins. The controller goes where the resistor goes, the fins are positioned inside the A/C duct. The proper name for this "resistor" is Blower Liner Controller, and it has 4 pins. Two pins control the blower speed, the other two are ground and signal. The speed control is done by the A/C ECU and the Controller. Not sure if the fins on the Controller are cooling fins to cool the Controller electronics, or a sensor to differentiate the A/C duct temp. from the cabin temp., then adjust the blower speed accordingly as to maintain the constant set temp.; might be both functions.

Anyways, I checked the control panel (*****), as per the repair manual section 55B, and all the continuity readings are as per factory specs. So, the blower dial and temp. dial don't seem to be the issue.

Regarding the relay. The manual and auto A/C systems, both use 4 legs of the relay, but you can use a 5-Leg relay, the relay connection has a "blind" female connection for the leg (Leg #4) that is not used. So, either a 20A 4-Leg or 30A 5-Leg relay will work. The correct one is 30A, so I changed to a 5-Leg. Mitsubishi OEM relay is 4-Legs, but 30A.

I could go on and on, but after going thru all the diagnostic procedures and checks related to the blower, as outlined in section 55B, the conclusion is a bad Blower Controller.

 

Unfortunately this is where all current car models are heading to... You've done some great diagnostics. I hope replacing blower control fixes the issue you are experiencing.

 

I know, actually the Denso 499300-2110 is the Denso P/N for the Montero, forgot Mitsubishi's MR P/N, but I have it written down somewhere. There is an OEM replacement made in China, but it is $130.00 at Aliexpress (including 2-3 day freight via FEDEX/DHL). All Denso 499300 are the same, but the last four (4) numbers change, that is the connector. Many popular vehicles use this controller (Toyota Highlander, Lexus, Scion, Nissan, Infinity, MB, Toyota Prius, Cadillac CTS, etc.), basically those with Automatic Climate Control. The last 4 numbers after the dash in the P/N are vehicle specific, basically the difference is the connector and pin positions; some are square with two rows of pins, others are rectangular with one row of pins, others are on the left, others underneath the part, etc.

Not difficult to diagnose, if you have the repair manual and have the patience to go step by step of the process. Now, if it was an electrical issue with a wire or connection, the Montero Ltd. has so many sensors, ECU's, etc. that it will take you quite awhile, though the repair manual is pretty good at guiding you. Having a Mitsubishi diagnostics tool helps greatly, but those are $500.00+ for the generic ones, and $1,000.00+ for the real ones. If I had one of those with the A/C ECU cable accessory, it would have taken couple of minutes to diagnose. The local dealers want $150.00 to diagnose, the mechanics that have one charge $100.00, and a car computer and diagnostics tools dealer here that does diagnostics only charges $50.00, but that is for OBDII readings, if it is one of the other Mitsubishi ECU's (A/C, ABS-MTACS, Security, etc.) that needs to be diagnosed and use another cable/connection adapter, then the price goes up to $75.00. I might go to them, but that is for an ABS/MTACS issue that I haven't been able to diagnose.

The part is $45.00 from a junkyard in Alabama, he guarantees it, but if it is not working I would have to pay freight back ($7.00). There is a lot of local junkyards that have Monteros, as it is a very popular vehicle in PR, but they don't open on Sunday, so will have to wait until tomorrow.