No Cooling Fan or A/C Clutch

M

mk8fanatic

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Ok guys
the other day I noticed that my Gen2 a/c would go from cold to warm over and over again as I drove it....Today I found that the A/C clutch would not engage at all, even when the low switch is jumped...Also no matter what I do the cooling fan will not come on. From what I can tell the fuses are good.. What can cause this and what Idea's may you have? Also I saw a small electrical puff of smoke come from the radiator area but the fan can spin freely by hand....Any help would be great...
 
VLCM module, mounted on the air suspension compressor bracket. i have a bunch tested in perfect working order. 9 times out of 10 this is the cause, this little black box, it controls your ac compressor and the cooling fan. if it is bad, neither one of them will work.

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i dont have any listed, i'll sell one outright!! i'll send you a pm. before i sell you one be aware that i am not a pro, i know a whole ton about these and worked on more than i care to say, but if you dont want a second opinion, if the one i send you doesnt fix the problem i'm not taking it back, i will exchange for another but i do not take them back. i always urge people to make sure before replacing electrical parts instead of just throwing parts at it. ford doesnt take back electrical parts and neither do i!!!
 
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Ok.....I know my way around these cars pretty well but this one has me stumped!.... I have two 97 marks, so what I did first was test the voltage to the fan and I got 12.8 So I obviously thought that the fan was fried...not the case. I swapped fan for fan on my two marks and the fan worked in the other car that had no problem and the fan that came out of that car that I know works did nothing! The only thing I can tell is that the other car has almost a full volt more to the fan but I wouldn't think much of this should I? Does anyone know why I would have power to the cooling fan but it not come on? And once again the fan thats in it is good. Also I have checked every fuse and swapped every relay.
 
mk8fanatic said:
Does anyone know why I would have power to the cooling fan but it not come on?
Click to expand...

Yep, I know why.

The VCLM is a solid state device, not a mechanical relay. You may be getting voltage - but you are not getting enough current. The in-rush current to start the motor is significantly higher than the highest current under load. You not only need voltage, but you need current as well.

That puff of smoke you saw was the current carrying capacity of the VCLM. :eek:

What I would be concerned with is the current condition of the fan motor. You could replace the VCLM only to fry another before the end of the cooling season. As the high capacity fan motors wear and age, the running current is higher than normal. This in turn puts a strain on the electrical system supplying such current and in this case the VCLM was likely the weakest link. It has been known to overload alternators and cause multiple failures of the charging system before the correct cause was found.
 
Cool Beans! I have replaced the cooling fan and the VCLM should arrive soon in the mail.. I will post the results when it gets here. Thanks again Driller! Guess sooner or later I will have to dabble in a little of everything on these two...lol
 
I rushed home to install the VCLM today and all I got was nada.:eek:

Could that puff of smoke been from the alternator? At the alt I have 14.3 volts.

I really hate to just keep throwing parts at this thing.

If I were looking for a bad ground where would I look first?
 
Just curious....but how are you testing the fan? Run power/ground to the fans to make sure they work.

Also, if you're trying to test if via the a/c controls, the high pressure switch could be bad and jumping the low pressure switch won't work if that is the case.


Oooo ooooo! Look what I found! This is some good info on the VCRM!

DESCRIPTION
The variable load control module (VLCM) controls:

the cooling fan motor operation and speed.
the A/C clutch operation.
other non-A/C functions.
turns the A/C clutch circuit OFF if the high-side pressure exceeds 2930 kPa (425 psi) .

ELECTRICAL SYSTEM
The variable load control module is connected electrically to the following:

powertrain control module (PCM) (12A650).
A/C high-side pressure sensor.
A/C clutch coil circuit.
cooling fan motor control circuit.


OPERATION

The cooling fan motor is controlled by the VLCM and control signals from the powertrain control module, which are sent on the data link connector (DLC) . Another feature of the VLCM is the ability to stop fan control operation at vehicle speeds of approximately 76 km/in (47 mph) and:

Cooling fan motor operation resumes when vehicle speed drops to approximately 68 km/in (42 mph) .
One exception is when the high-side pressure is above 2069 kPa (300 psi) .
The fan control does not shut off when the high-side pressure is above 2069 kPa (300 psi) .

If an A/C pressure sensor failure occurs, the fan control continues to operate.
NOTE: The following is a general description of VLCM operation. Refer to Powertrain Management for detailed information.


The VLCM receives constant signals from the A/C pressure sensor which monitors the refrigerant system high side (discharge) pressure. The A/C pressure sensor signal from the VLCM is sent to the powertrain control module over the J1850 communication network.

When the high side pressure is less than 1034 kPa (150 psi) , the cooling fan motor speed is 1000 rpm .
As pressure increases above 1034 kPa (150 psi) , the VLCM begins to increase the cooling fan motor speed.

At 2034 kPa (295 psi) , the cooling fan motor speed is 1800 rpm (full speed).
If the high side pressure reaches 2930 kPa (425 psi) , the VLCM interrupts the A/C compressor circuit to stop A/C compressor operation while the fan control continues to operate.

At 1379 kPa (200 psi) , the VLCM closes the A/C clutch circuit to resume A/C compressor operation.



Here are some electrical diags......
VCRMElec3.gif

VCRMElec.gif

VCRMElec2.gif



Hope this helps! :smile-purple:
 
The only thing new that told me was that the cooling fan will remain to run at all A/C psi. Oh and that the vclm ground is the black #1 wire on the harness.

Guess should I try to ground that pin to the battery neg?

Have any idea where the other end of that ground is? I could check it for continuity.

I have a lifetime guarantee on the alternator so I guess I can swap that out with a new one to see what it does.

I tested the fan with direct leads from the batt....it works.

The fan gets power sure enough...I just don't know about the ground.
 
You need to test both sides of the power/ground.... :D

The alternator will NOT have anything to do with the fan/VCRM. The VCRM and fan work without the engine running.

Sorry that I gave you all that info....just trying to help.
 
The ground wire should go to the header panel behind the driver's side headlamp. Remember what I said before, you may have voltage but not the current carrying capacity. Check the fuse for the cooling fan circuit in the power distribution box under the hood. Double check your fuse links as well.
 
Ok...I will recheck the fuses in the power distribution box...

This may sound dumb but...fuse links?

is there something under the hood I don't know about?
 
mk8fanatic said:
Ok...I will recheck the fuses in the power distribution box...

This may sound dumb but...fuse links?

is there something under the hood I don't know about?
Click to expand...

Follow the battery feed to the power distribution box. It should go to a stud for a junction point where a couple gray 'wires' split off. Those 'wires' are actually fusible links which should lead to the alternator.
 
Ok...I found them...they look ok from what I can actually see. Tomorrow I will try to follow them under the box as far as I can...It looks like they go into a larger harness...how far should these gray fusible links go on?..Would the break relatively close to the box?
 
You'll prob have to OHM them out to really check them. If the fuse blows, you'll loose the voltage thru the link.
 
Whats funny is that there is no reference in the manual as to what fuse operates the fan/ac..I would like to replace it even if it looks ok, but I would rather not replace them all.
 
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