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Electric fan behaviour
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=1&t=88007		 Page 1 of 1
Author:  casm [ Wed Apr 11, 2018 11:14 pm ]
Post subject:  Electric fan behaviour
We're getting our first run of warm (80°F) weather here, and I've started running the A/C as a result. Unlike nearly every vehicle I've had in the past with A/C, the electric fan does not appear to run when the A/C is on (or off, for that matter). This is doubly odd as I have an HDS thermostat fitted and it's running at 203°F.

What is the expected behaviour of the electric fan with the A/C on and off? Are there any common failure points (grounds, electrical connectors, etc.) that I should look into? I haven't had a chance yet to put 12V directly to the fan, so don't know if it's shot or not.
Author:  Billybob [ Thu Apr 12, 2018 2:17 am ]
Post subject:  Re: Electric fan behaviour
Lots of people have this problem on the CRDs....my 2002 Export CRD does not have that front fan fitted so I cannot do any comparisons on my Jeep. The fan should switch ON with the AC ON and the Jeep is at a certain temperature and likewise when the engine starts to get very hot the fan should kick in.

A lot of members have reported that if they pull out either the fan High speed relay or the fan Low speed relay or both then the fan runs.
I personally cannot see from the wiring diagrams how this could be possible but the wiring diagrams do have a lot of errors in them!

If you do not already have the 2005 KJ Service Manuals then download them here...includes the "wiring diagrams" and use them with discretion to see if the motor does get power to it ie. +12 volts on one side and a good ground on the other side and that the fan has not seized up. Also try swap out the two relays involved with similar ones.

I am sure you will get a lot of Members chipping in here soon as it is a common problem and hopefully some owners have found what the problem is....you can do a search here and there are a lot of hits but also a lot of these hits are for the interior blower motor! :?

KJ Manuals: http://www.colorado4wheel.com/manuals/Jeep/KJ
Author:  flash7210 [ Thu Apr 12, 2018 12:42 pm ]
Post subject:  Re: Electric fan behaviour
For a CRD, the electric fan usually turns on one of two ways.
1. engine coolant temp gets up to or above 205 F
or
2. the AC is turned on
But for the AC system to kick on the fan, the AC pressure switches have to send a signal to the ECU to turn on the fan. (I cant remember if its the high pressure switch or the low pressure or both)
So, if a pressure switch is bad, or if Freon level is low, the ECU may not get the signal.

Also note that the electric fan may not turn on immediately when turning on the AC. There is a delay.
After driving several minutes with the AC on to get things warmed up, pull off into a parking lot, leave everything on and running, and look into the grille to see/hear if the fan is running.

If you want to test the function of the electric fan, turn the key on and pull any one of the two fan relays. This will cause the fan to always be ON at low speed.
Pulling both relays will cause the fan to always be OFF.

If the fan does not come on when pulling a relay then you have a bad fuse or wiring problem.
Author:  WWDiesel [ Thu Apr 12, 2018 12:53 pm ]
Post subject:  Re: Electric fan behaviour
flash7210 wrote:
For a CRD, the electric fan usually turns on one of two ways.
1. engine coolant temp gets up to or above 205 F
or
2. the AC is turned on
But for the AC system to kick on the fan, the AC pressure switches have to send a signal to the ECU to turn on the fan. (I cant remember if its the high pressure switch or the low pressure or both)
It's the high pressure switch.
So, if a pressure switch is bad, or if Freon level is low, the ECU may not get the signal.

Also note that the electric fan may not turn on immediately when turning on the AC. There is a delay.
After driving several minutes with the AC on to get things warmed up, pull off into a parking lot, leave everything on and running, and look into the grille to see/hear if the fan is running.

If you want to test the function of the electric fan, turn the key on and pull any one of the two fan relays. This will cause the fan to always be ON at low speed.
Pulling both relays will cause the fan to always be OFF.

If the fan does not come on when pulling a relay then you have a bad fuse or wiring problem.
Or a bad fan motor.
Author:  GordnadoCRD [ Thu Apr 12, 2018 1:42 pm ]
Post subject:  Re: Electric fan behaviour
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=84884&p=908365&hilit=+PT+cruiser+#p908365
Author:  casm [ Thu Apr 12, 2018 9:30 pm ]
Post subject:  Re: Electric fan behaviour
Appreciate the pointers, everyone.

Did the relay pull test. The fan is coming on as expected when I do that, so at least that's functional.

At this point I'm leaning towards two possibilities:

1) Something is causing the PCM to not turn the A/C fan on when it's needed.

2) The mechanical fan's clutch is already shot after 6 months.

What temperature should the electric fan kick in at? I'm finding varying answers on this and would like to know because if it's set for 205°F and I'm running a 203°F thermostat (reading typically around 201-202°F via OBD), it should be fairly easy to get the electric fan to kick in, but it isn't.
Author:  casm [ Sun Apr 22, 2018 10:35 am ]
Post subject:  Re: Electric fan behaviour
Had some fairly solid rain yesterday while out running errands. We're in and out of the Jeep, getting soaked and bringing in moisture with us whenever we get back in.

Noticed that the defroster wasn't keeping up with defogging the windows. Didn't hear the A/C compressor cycling incessantly, but suspect that the refrigerant levels may be low, causing the pressure switch to deactivate the system. This may be playing into fan operation, and I'm considering running a secondary temperature sensor off of the HDS thermostat to kick in the fan relays as a backup.

Also noticed a couple of days ago - after commuting during 85°F heat with the A/C running in start/stop and freeway traffic for 45 minutes - that fan clutch lockup appears to be weak at best. Just replaced that in October with a Hayden 2905; will seek out a warranty replacement and see if it makes any difference.
Author:  WWDiesel [ Sun Apr 22, 2018 12:34 pm ]
Post subject:  Re: Electric fan behaviour
casm wrote:
Had some fairly solid rain yesterday while out running errands. We're in and out of the Jeep, getting soaked and bringing in moisture with us whenever we get back in.
Noticed that the defroster wasn't keeping up with defogging the windows. Didn't hear the A/C compressor cycling incessantly, but suspect that the refrigerant levels may be low, causing the pressure switch to deactivate the system. This may be playing into fan operation, and I'm considering running a secondary temperature sensor off of the HDS thermostat to kick in the fan relays as a backup.
Also noticed a couple of days ago - after commuting during 85°F heat with the A/C running in start/stop and freeway traffic for 45 minutes - that fan clutch lockup appears to be weak at best. Just replaced that in October with a Hayden 2905; will seek out a warranty replacement and see if it makes any difference.

If your freon charge is low enough that it does not allow the low pressure AC switch to close, this will keep the AC compressor clutch from engaging and thus the high pressure AC switch will never close which is what triggers the electric cooling fan relay via the ECM... :roll:

as to cooling,
The GM 11 blade fan with the larger serere duty V8 Hayden clutch 2986 might interest you?
See this thread for more information:> viewtopic.php?f=5&t=82941
Author:  casm [ Sun Apr 22, 2018 4:53 pm ]
Post subject:  Re: Electric fan behaviour
WWDiesel wrote:
If your freon charge is low enough that it does not allow the low pressure AC switch to close, this will keep the AC compressor clutch from engaging and thus the high pressure AC switch will never close which is what triggers the electric cooling fan relay via the ECM... :roll:


Yep. The weird thing is that the A/C was ice-cold in the heat a couple of days prior. Then again, the refrigerant could be borderline enough that depending on changes in temperature, etc. the pressure varies just enough to either close the switch or not - or the switch itself could be flaking out. Need to do a bit more investigation, but it's an interesting data point.

Quote:
as to cooling,
The GM 11 blade fan with the larger serere duty V8 Hayden clutch 2986 might interest you?
See this thread for more information:> viewtopic.php?f=5&t=82941


I see you've had that in place for about 2.5 years. How's it performing, and is there anything you don't like about it or would have done differently?
Author:  WWDiesel [ Sun Apr 22, 2018 9:43 pm ]
Post subject:  Re: Electric fan behaviour
casm wrote:
I see you've had that in place for about 2.5 years. How's it performing, and is there anything you don't like about it or would have done differently?

It performs perfectly and I would not change a thing! I did modify the fan shroud and made it a two piece when I installed the GM setup.

The fan is a little noisy (air noise), but it sure makes a huge difference in AC performance in stop and go traffic during the summer when temps are 100+ degrees when driving....
And I am sure it helps in other areas as well during adverse temperature operating conditions...
Author:  casm [ Tue Apr 24, 2018 3:09 pm ]
Post subject:  Re: Electric fan behaviour
Sprayed the daylights out of the fan relay connectors with contact cleaner over the weekend. Got home after driving around in 80°F weather today with the A/C on, and the electric fan had kicked in. Hopefully that's all it needed, but think I will have the refrigerant levels checked regardless.

In other news, the local NAPA had the GM 11-blade fan in stock, so picked up one of those, and Rockauto has the Hayden 2986 fan clutch going out to me today. Hopefully that one will arrive before the weekend, and I'll be able to install them on either Saturday or Sunday.
Author:  WWDiesel [ Tue Apr 24, 2018 3:23 pm ]
Post subject:  Re: Electric fan behaviour
casm wrote:
Sprayed the daylights out of the fan relay connectors with contact cleaner over the weekend. Got home after driving around in 80°F weather today with the A/C on, and the electric fan had kicked in. Hopefully that's all it needed, but think I will have the refrigerant levels checked regardless.

In other news, the local NAPA had the GM 11-blade fan in stock, so picked up one of those, and Rockauto has the Hayden 2986 fan clutch going out to me today. Hopefully that one will arrive before the weekend, and I'll be able to install them on either Saturday or Sunday.

Good move! :BANANA:

A tip for removing the mechanical fan!
Once the shroud is unbolted, it can be pushed back against the engine far enough to slide a piece of protective material in place!
Slide either a piece of thick cardboard or thin sheet metal or poster board in front of the fan up against the radiator so if the fan were to happen to drop or fall forward during removal for any reason, it's metal blades will not damage the radiator... :wink: Trust me, it can happen :roll:

Post how you like it after install. Convert your fan shroud into a two piece shroud if you have not already done so, see diagram below... :D Makes life a lot easier! :-)r


Image
Author:  casm [ Tue Apr 24, 2018 4:27 pm ]
Post subject:  Re: Electric fan behaviour
WWDiesel wrote:
Good move! :BANANA:

A tip for removing the mechanical fan!
Once the shroud is unbolted, it can be pushed back against the engine far enough to slide a piece of protective material in place!
Slide either a piece of thick cardboard or thin sheet metal or poster board in front of the fan up against the radiator so if the fan were to happen to drop or fall forward during removal for any reason, it's metal blades will not damage the radiator... :wink: Trust me, it can happen :roll:

Post how you like it after install. Convert your fan shroud into a two piece shroud if you have not already done so, see diagram below... :D Makes life a lot easier! :-)r


Funnily enough, someone else had been in there before me and had a similar thought regarding the fan shroud - when I replaced the first fan clutch last October, the bottom half had already been notched to allow the shroud to pull up and out past the fan shaft. They even put a piece of finishing plastic in there to prevent ice, rocks, etc. from getting kicked up into the shroud.

I'll probably leave it as-is since it's done, but the two-piece method you're describing would work just as well.

And yep, I'm a believer in putting anything relatively soft and shock-absorbing between the fan and radiator when pulling these things out. I didn't do that many years ago on a Ford Capri I had, and learned the hard way what a radiator costs to replace as a result.
Author:  WWDiesel [ Tue Apr 24, 2018 9:41 pm ]
Post subject:  Re: Electric fan behaviour
casm wrote:
And yep, I'm a believer in putting anything relatively soft and shock-absorbing between the fan and radiator when pulling these things out. I didn't do that many years ago on a Ford Capri I had, and learned the hard way what a radiator costs to replace as a result.

Good, sounds like you have been educated as well by the same school of hard knocks that many of us have already had to learn the hard and sometimes costly way..... :banghead:
Experience can be one hell of a teacher!!! :ROTFL:
Author:  casm [ Fri Apr 27, 2018 10:43 pm ]
Post subject:  Re: Electric fan behaviour
Finished up the 11-blade fan upgrade today; got held up by the fan bolts from the Hayden 2905 not being even close to compatible with the 2986. Details on that here, including the GM part number (11516869 for the impatient) for the bolts you'll need.

I'll see how it does over the next couple of weeks, but initial impressions are basically favourable. With an HDS thermostat housing and 203°F thermostat installed, the needle on the temperature gauge was just slightly under 12 o'clock. Previously, it had been at or just slightly over that spot most of the time.

Fan noise isn't appreciably increased over stock, at least not while moving at up to 50mph. I'll see how it does on the freeway tomorrow, but don't expect much difference.

One thing I did notice was that when the electric fan comes on, there's a fair amount of forward air pressure from it around the outside of its fan shroud. This isn't surprising in that the electric fan's shroud doesn't make a positive seal with the A/C condenser, but it does feel like there's more air being deflected outward than there should be. I may just need to pull the front clip and fan and clean out 13 years of accumulated bug splats and road grime.
Author:  WWDiesel [ Sat Apr 28, 2018 12:06 pm ]
Post subject:  Re: Electric fan behaviour
casm wrote:
Finished up the 11-blade fan upgrade today; got held up by the fan bolts from the Hayden 2905 not being even close to compatible with the 2986. Details on that here, including the GM part number (11516869 for the impatient) for the bolts you'll need.

Yes, you are quite correct, the Hayden 2986 & GM 11 blade fan setup requires four (4) of the 11516869 bolts.
If I remember correctly, they have different threads and are a bit larger?? :roll:
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