08 TC elec cooling fan does not run, diagnose?

[jaywish]

Sitting stuck on a line the engine temp pegged. ASAP pulled into a spot. The engine fan was not on.

Engine cooled to normal then I drove it home in light to moderate traffic it did not get hot. From this I am AOK with thermostat functioning.

I did visually check the 50A cooling fan fuse. Looks good.

I spun the fan by hand and it moves freely.

The gauge worked and the idiot light as well.

I do have the manual and could get the diagnostic tree etc. But my time to work on anything is really constrained due to severe family issues at this time.

I hope there is a quick, 'It is usually this...' kind of thing solution.

There is this "cooling fan control module" mounted on the fan shield.



Since the gauge worked I guess sensor is ok. Is there a second sensor to run the fan?

So quick way to figure this?

[jaywish]

Remember "Hold CTRL & click on photo" to expand photo if necessary

[jaywish]

I guess it could also be a pcm issue but would not be my first guess though that is why I am asking for experiences.

[sly]

The PWM Module on the fan is the most common failure point from what I've seen. I think they started using those in 03? Anyhoo... the PCM controls the fan. If power to the fan is good and the wires are ok, then most likely it's the motor windings or the PWM module. Unplug the fan from the module and check resistance. If you get around 0.4-0.6 ohms (something less than 1 - touch the meter leads together to make sure you subtract the meter's own resistance) then the fan motor should be fine. If that's the case, then it's most likely the fan control module. This is why I prefer the two speed fans (two wires to the motor - low through a resistor, high bypasses the resistor) as they're less prone to random failures like this.

[friskyfrankie]

On a '96, I once found a short in the wiring to the fan and fixed that. All was well. Can you apply 12 volts directly to the fan to make sure the motor is good? If that works, you can then work backwards (as time allows) to find the issue (relay, module, wiring, etc).

[jaywish]

Sounds like a plan.

Thanks. When I proceed I will post back.

Maybe I could sneak out enough time tomorrow to check the motor windings. I was going to start checking for power etc while the engine was cooling but the darn Batteries got crusty in the brand new cheap vom I had added to the emergency tool kit. Guess I will keep them in a bag not in the meter. Though I needed a #0 Phillips to open the meter. fortunately my pocket knife had that.

In 2018 I had replaced ALL the hoses just because I was changing the coolant. Now I am glad as nothing opened up and peed all over the road.

[jaywish]

Does the control module require thermal grease or just a clean contact surface?

[sly]

No. The back side is exposed to the fan and is the heatsink itself (fins and all). No grease. Clean, yes.

[jaywish]

Thanks. did not want to find out while I was potentially installing it. The grease is one item I don't have in stock. Still can't get out to the vehicle for quick diagnosis.

[jaywish]

Ok, yesterday I got someone to give me 45 minutes so I checked the car and grabbed a shower. Don't know which one I was happier about.

Both electrical plugs came off like butter. The one attaching hardware component is a #2 Phillips head screw located just below the upper connection socket. If they had used a hex or torx bolt this would have been a snap. Not that it was hard by an means just slightly inconvenient particularly as you could not quite go straight into the screw. The other end of the module is held in by two big flanges which insert into fan shroud. Easy Peasy.

The fan rung out at .4ohm. so good news there. Checked the leading plug for voltage first which was present (key Off), then for ground on the pin without voltage and low resistance so good on the supply side.

Ordered a STANDARD MOTOR PRODUCTS RY1608 unit at local flaps. $169. (No more discounts for me as everyone I used to know is either retired or dead) $169 same day would have been OK as I wanted the car usable. On delivery then the part showed Made in China. Since I special ordered it I installed it. gently cleaned connectors and applied a light silicone film. Fan cycles AOK now. Thanks Sly. Very glad it was not the PCM or related wiring.

If I had known that the new part was China made I would have ordered the Motorcraft unit on RockAuto for $128 plus express shipping or possibly sourced at the dealer. Not that it will change the world but I sent an Email to Standard about the China made component. That was the first Standard brand high line part (not "T" series) made in China that I have come across. I am not really worried about short product life, as I would with Dorman or no-name, as likely Standard exercises good quality control but still....

[friskyfrankie]

Too bad you had a time issue because Amazon has it for around $55 (would take a few days to get). Didn't check Summit or anyone else.

[friskyfrankie]

According to Amazon, this is made in the USA (not sure how accurate they really are about this).

https://www.amazon.com/Standard-Motor-Products-RY-1608-Relay/dp/B00985AVPW

[jaywish]

That is what I wanted.

This is what I got.

Note the new stick-on label

[jaywish]

Also on my screen it states "Does Not fit 08 Town Car" I guess I will have to be more judicious in using that Amazon feature since this part did not show for me when I originally searched Amazon for it. Came up with your link.

[sly]

Yeah... do NOT trust Amazon's part fitment. Find the part number you need and then search amazon for that part number.