tool

Can you explain how you wired this switch in?

I would like to do this on my truck.

jmlcolorado

I'll check the wires this evening to
See what I jumped.
Basically the computer controls ground to engauge/disengage the fan clutch. I used a cheap wire tap for now (not recommended for prolonged use as it will corrode) and tapped the ground. This wire goes into the cab to my switch then the other leg of the switch goes to a ground point. That's it.
The disadvantage I see is the fan is full on with the switch on. When you switch it off, it takes a few minutes for the fluid to disengauge the clutch.

If your fan clutch works fine normally. It probably wouldn't be so bad since it'll control the fan like normal, then you have the ability to lock the clutch full on.
With a proper working system. I don't really see a point to add the switch but that's JMHO.
It just bothers the crap out of me to have the fan screaming full blast, or dead. No in between.

Maybe a potentiometer so you can adjust how full
The fan kicks on. I think the computer creates pulses to control how much to engauge the fan.

If I were to make this a permininate fixture, the wires would be soldered, heat shrunk a few times, taped, then wire loom installed.

tool

Thanks I appreciate it!

jmlcolorado

I forgot to tell you which wire this was! Sorry

The wire I have a ground tied into is the Light Green wire at the fan plug under the front passengers side. Is technically called "park lockout solenoid control".
White is sensor supply.
Orange is fan speed sensor.
Black/lt blue is sensor ground.
Dark blue is fused ignition switch output (run).

I've been working trying to diagnose the fan not running and I've traced all these up to the passengers firewall, large plug with 14 wires going into it. It's mounted near the hood at the far right side of the truck. These wires go into the wiring channel above the engine.
If your going to tie a switch in, I'd do it here to help keep your connection cleaner and avoid running one wire all the way to the fan.

jmlcolorado

Me, on the other hand, want the darn fan to run as it should! SO, I broke out the meter and have started texting continuity starting at the fan plug.
Put a lean on the Light Green wire, which is what I ground out to fire up the fan, then separated the connected on the passengers side firewall near the hood.
Good conductivity on this wire between these points.
So next, I hooked my meter to the male pin on the other half of this connector so I could test the wire from the passengers side all the way over to the giant wire connector on the drivers side. This is mounted to the firewall directly behind the battery.
This plug has a 7mm bolt holding it together and has all the wiring for the front of the truck into it. I counted 35 wires going into it.

SO, in theory, with this plug separated from the supply side, each wire has an "open circuit" right?
So I SHOULD be able to identify (I'm color blind In greens, reds and browns, so I have to do things a bit differently then most) the one single wire I have my lead attached to on the passengers side plug, right?

I SHOULD only hear a tone on ONE female pin on this plug since the wire only goes to one pin. BUT, I get a tone on 5 separate pins!
What gives? How is this possible?


Edit: never mind. I took the wire channel apart and found that the light green wire goes into this, but doesn't go all the way to the drivers side. It exits the back of the Chanel and heads down in wire loom.
This goes to a few connectors bolted to a bracket on the trans bell housing.
Wish I woulda known this when I was doing the clutch a couple weeks ago. I would have tested the connection then!
Sure seems like this wire is good all the way to the ECM.

Green_Machine

Be sure to check the connector near the bumper...mine was damaged slightly which allowed corrosion to occur in the connector(there have been a few around here) which caused the fan to not work.

Easy fix if that's what it is!

Chay

jmlcolorado

I was readying that on a few other threads the other night. Seems so simple to miss
I'm on it!

maddog1927

My findings as well are no continuity anywhere except between 1 and 6, and also 7.5 ohm. on my old clutch 150K and new o'reilly .

Also a little confused on pin #'s. Is it like this?

Lock Tab
123
456
4 being the empty spot

My problem is fan does not come on and heats pulling trailer up hill. OE fan, but wires were cut and I spiced them. Ive been throwing p0480 codes since about day one.

Probably a waste of money, but I'm gonna try a new clutch 1st.

jmlcolorado

Same problem I'm having now. No fan kick on.
I ended up wiring a manual switch, but ita a PItA to switch off and on when needed.
I THINK if you look at the female side of the plug, it designated a couple PIN numbers. Or maybe just the number 1 pin.
My wires were never cut.

maddog1927

OK I found the pin numbers on the back of the female plug. Thanks Jim.

earlier in the post you said you might take it to the dealer for his scan tool, have you tried that yet?

jmlcolorado

I haven't gotten to it yet. I've been buried up to my eyebrows in work this summer.

Vanellies

Where is this plug located? I see the one where the fan clutch connects, but you said there is another connector close to the bumper?

Green_Machine

It's been a long time, but what I remember is that the plug (Keep in mind it's a 2003) was up near the bumper on the passenger side. Can't remember if it was tied to the body or??

Chay

Vanellies

I replaced my fan clutch the other day. I still don't here it spin up when its up to running temp and idling, the temp gauge still goes over 200. I decided to switch the AC on to see if it would engage then. Still nothing and AC is blowing warmer air. Something that is really strange is when I'm driving and have the AC on it blows cold air, so my guess is that the fan clutch isn't engaging, am I right?

Any known fixes? I'm guessing wiring might be bad or even WORSE yet the ECU is faulty.

Van

jmlcolorado

Probably not the ECM but could be the ICM (Intergrated Control Module). This controls all the lighting, switching, and I understand the fan clutch as well.
Dealer can flash this and see if it's the problem.
I also understand that we can not replace these ourselves as the new ICM needs to be flashed by the dealer to match the truck.

I've just wired the switch I mentioned above. It's a PItA but it's been working fine for now till I get enough down time and $ to have the dealer replace the ICM.