Electric Cooling Fan Protocol

tigafila · **Posted:** Thu May 29, 2014 3:10 pm

Hello all, my pusher fan died and I'm planning a little different system. Does anyone know the protocol of the electric cooling fan? I've been pouring through the FSM and can't find it. Specifically I need to know under what conditions the fan runs on high/low, is it just used for a/c or will the pcm turn it on by coolant temp. Please help with any info.

Thanks, Tigafila!

flash7210 · **Posted:** Thu May 29, 2014 3:15 pm

I dont know the exact fan speed, but my testing has shown that the fan comes on at about
205 deg F and turns off at about 190.

Of course, this is with the A/C off.

tigafila · **Posted:** Thu May 29, 2014 9:39 pm

That's very helpful, any other info out there?

Thanks, Tigafila

papaindigo · **Posted:** Fri May 30, 2014 7:30 am

Thoughts that might or might not help much:
1. did the fan really die as in burned out or is it just not running?
2. if the latter it could be bad relay(s), swap to check, or bad wiring, provide battery power directly to fan and see if it runs if so trace wires.
3. I don't know the exact specs on what triggers it but I "think" it's an ECU signal based on senor input, possibly engine coolant temp and/or AC sensor. I'd bet Keith at GDE knows, drop him an email.

tigafila · **Posted:** Fri May 30, 2014 9:54 am

Thanks papaindigo, that's a great idea, I know Keith was testing something similar. I can't find Keith's email, anyone have it?

Thanks, Tigafila

dieseldawg · **Posted:** Fri May 30, 2014 1:49 pm

I wish I could understand the fan logic myself as I am trying to troubleshoot weak A/C performance. I know on my CRD, if you pull either the high speed or low speed relay while the engine is running, the fan will turn on and run at a speed, I think low based on sound. I looked at the wiring diagram and one speed is tied to the normally closed side of the relay, and the other is activated when the relay is activated. I just can't picture how that is controlling the fan. Seems like it should be a relay on or relay off type of deal for either low or high speed.

flash7210 · **Posted:** Fri May 30, 2014 3:08 pm

The fan motor has two field windings.
Energize either one and you will get low speed.
Energize both and you will get high speed.

LibertyFever · **Posted:** Sun Jun 01, 2014 8:37 pm

Does the diesel use the same electric rad fan as the gassers?

I have a gasser with the trailer package which means I have a clutch fan on the water pump and a two speed rad fan.
I've have my share of problems with the electric fan. If the windings arent open or the brushes shot you can repair them.

Sent from my SGH-I747M using Tapatalk

tigafila · **Posted:** Mon Jun 02, 2014 9:51 am

Thanks Liberty Fever and others, the fans and protocol are different on the CRD and gasser, still trying to pin it down.

papaindigo · **Posted:** Mon Jun 02, 2014 10:11 am

tigafila - to contact Keith just use the regular GDE support email address (support@greendieselengineering.com) but be advised they are on vacation until 6/5.

tigafila · **Posted:** Mon Jun 02, 2014 1:51 pm

Thanks Papaindigo, I have an email in since Friday and got the autoreply about the vaca.

zak21 · **Joined:** Fri Sep 27, 2013 8:57 pm **Posts:** 17

I found it in the FSM 7-58, it is a little confusing. The first section makes you think that it is on all the time with the AC but the next says with AC & coolant temp but I think it is the latter. Also there is no distinction in the FSM between CRD and gasser for this fan.

Vehicles Equipped with AC: In addition to using coolant temperature and battery temperature sensor to control
cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay
is also energized when air conditioning is selected and coolant temperature is above 95° C (203° F), or , air conditioning
is selected and battery temperature sensor is above 41° C (106° F). It will then de-energize when air conditioning
is selected and coolant temperature is below 92° C (198° F), or air conditioning is selected and battery
temperature is below 38° C (100° F).

tigafila · **Posted:** Sat Jun 14, 2014 6:33 am

Thank you Zak!

WWDiesel · **Posted:** Sat Jun 14, 2014 9:47 am

Found this:
Hope it Helps? :mrgreen:

Note: You can click on the wiring diagrams and enlarge them for better viewing!
WWDiesel :JEEPIN:

OPERATION The electric radiator cooling fan is controlled by the Powertrain Control Module (PCM) through the radiator cooling fan relays. The PCM regulates fan operation based on input from the engine coolant temperature sensor, battery temperature sensor,air conditioning select switch and vehicle speed. The fan is not energized during engine cranking regardless of the electrical input from the temperature sensors and air conditioning switch. However, if engine operation conditions warrant fan engagement, the fan will run once engine starts. On vehicles NOT equipped with AC:

The relay is energized when the coolant temperature is above 80° C (176° F), or battery temperature sensor above –12° C (10° F). It will then de-energize when coolant temperature drops below 82° C (180° F), or battery temperature sensor below –9° C ( 16° F). Vehicles Equipped with AC: In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay is also energized when air conditioning is selected and coolant temperature is above 95° C ( 203° F), or , air conditioning is selected and battery temperature sensor is above 41° C (106° F). It will then de-energize when air conditioning is selected and coolant temperature is below 92° C (198° F), or air conditioning is selected and battery temperature is below 38° C (100° F).

More:
The A/C high pressure switch controls the electric cooling fan operation by monitoring refrigerant line pressures. When the A/C discharge line pressure rises above 1900 to 2200 kPa (280 to 320 psi) the fan will turn on. The cooling fan will turn off when the A/C discharge line pressure drops to 1600 kPa (235 psi).

Wiring Diagrams:
1;

2.

3.

4.

papaindigo · **Posted:** Sat Jun 14, 2014 10:26 am

That write up may or may not be at least partially correct as the editors of the FSM were/are not the best in the world. In fact I often wonder if the writers of any such manual have any grasp of the topic they are writing about but that's a different issue. At any rate the 05 and 06 CRDs, at least the US ones, do not have a battery temperature sensor (I've looked for it) and I don't know in what prior year(s) that sensor was, in fact, installed.

WWDiesel · **Posted:** Sat Jun 14, 2014 10:38 am

papaindigo wrote:

That write up may or may not be at least partially correct as the editors of the FSM were/are not the best in the world. In fact I often wonder if the writers of any such manual have any grasp of the topic they are writing about but that's a different issue. At any rate the 05 and 06 CRDs, at least the US ones, do not have a battery temperature sensor (I've looked for it) and I don't know in what prior year(s) that sensor was, in fact, installed.

You are correct Pap as I see nothing in any of the wiring diagrams showing a feed from a battery temperature sensor!
:roll:

tigafila · **Posted:** Sat Jun 14, 2014 11:14 am

This group is so awesome! I was able to exchange emails with Keith and he confirmed some things for me as well. Soon I hope to be posting a simple and inexpensive electric fan conversion.

sonnydaze · **Joined:** Fri Apr 04, 2014 4:55 pm **Posts:** 16

tigafila wrote:

This group is so awesome! I was able to exchange emails with Keith and he confirmed some things for me as well. Soon I hope to be posting a simple and inexpensive electric fan conversion.

please keep us posted

Electric Cooling Fan Protocol

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