Electrical fan runs constant and glow plug indicator quit...

cxturboboost · **Posted:** Sun Dec 11, 2011 8:58 pm

Hello all,

My electrical fan is running from the time you turn on the key and won't shut off. I also noticed the glow plug indicator won't come on now matter how cold it is? Any ideas? It starts fine so glow plug must be working even in 20 degrees...

Thanks for any help!

Pete

Joe Romas · **Posted:** Mon Dec 12, 2011 8:08 am

Two things come to mind. One a sensor or wire to it is shorted telling the ECM the engine is hot. Second is the fan relay is shorted but that shouldn’t cause a GP problem. You could pull the fan relay and replace it with one say from the AC or something as a test.

If it were me I would hook up my vag-com unit with the engine cold and see how warm/hot the ECM thinks the engine is and start from there.

If yours is an 06 check the wire harness that runs behind the fuel filter head bracket for being scuffed or bare :JEEPIN:

papaindigo · **Posted:** Mon Dec 12, 2011 8:48 am

Sounds like 2 different things. Two thoughts:
1. on the glow plugs remember the like only comes on for lin 2 seconds so it's easy to over look and I agree it sounds like the plugs are working. So try the instrument cluster test which can be invoked by holding the trip odometer button while turning the ignition on. It will cycle through all bulbs and gauges including, I think, the glow plug light but perphaps Joe can confirm. If the glow plug light does not come on either the test doesn't activate it or you have a bad LED bulb. If the latter the dealer will want to replace the entire instrument panel for som $700+ or you can do what lgoodbar did which is pull the panel and solder in new LED or have someone do same.
2. on the heater fan Joe's idea is a good one but if that doesn't do it check the fan resistor. I know when it goes bad the fan won't run but perhaps there is a failure mode that keeps the fan always on. To get to the resistor open the glove box then press inward on the latch arms on the left and right side to let it drop down further. The resistor is right there held on by two 5/16 hex head screws. You need to pull out on the red tab about 1/4" to push the release and it required some pressure to get the red tap to pull out. The replacement is a heavy duty resistor for a 2001-2004 Chrysler Sebring.

cxturboboost · **Posted:** Mon Dec 12, 2011 9:33 am

Hi guys,

I did the full instrument check, and swapped the relays already... NO Go.... The light is working fine on the dash as it did come on for about 2 seconds this morning when I looked and when performing the test...

It's not the heater fan that is running, its the fan in front of the radiator/intercooler... I call it the auxillary engine electric fan?

I dont' have a reader to be able to tell where the ecm/pcm thinks temps are at? The gauge however is functioning properly. Do they get their feed from the same sensor?

Thanks for all the help!

Pete

papaindigo · **Posted:** Mon Dec 12, 2011 10:44 am

Ok if I have this right your instrument cluster glow plug light is working fine (e.g. it comes on for about 2 secs at start-up) you just did not notice it in the recent past. No biggy while I am aware of that light I never really notice it coming on and lots of folks who have owned older diesels sort of expect that if it does not stay on for a significant period of time that there is a problem but remember we have "fast" glow plugs.

If the electric fan just behind the grill is running that fan is linked to AC performance not so much engine temp although the 2006 FSM refers to it as a radiator electric fan. I suspect whatever sensor activates the fan has died in the "on" position but I'm not enough of a CRD electrical system person to offer an opinion as to where that sensor is. As an interim solution if you are not using your AC you can try pulling the R34 or R40 relays in the power distribution center to see which one turns the fan off which also might help in locating the problem.

Joe - comments?

racertracer · **Posted:** Mon Dec 12, 2011 12:23 pm

Are you guys sure you are looking at the correct indicator light for the glow plugs.

The glow plug indicator light is located at the top northwest corner of the instrument panel and it looks like a yellow curley cue french fry.

It is not at the bottom left of the instrument panel .

Mine goes on and off at the speed of light below 30 degrees, not even a second.

Are we talking about the same indicator light?

cxturboboost · **Posted:** Mon Dec 12, 2011 8:25 pm

The service manual says the battery temp sensor also effects the fan? The temp gauge in the instrument cluster is functioning normall, so I'm not sure if there is any other temp sensor or if it all pulls off the single one in the head?

Pete

Joe Romas · **Posted:** Mon Dec 12, 2011 8:41 pm

When I replaced my Optima a month ago with a Sears P1 I didn't see a battery sensor :juggle:

I know what they are because my 00 XJ has one :mrgreen:

Section 7 of the FSM has a list of things to check when the electric fan stays on for the GASOLINE powered engines but nothing for the CRD's :banghead:

papaindigo · **Posted:** Tue Dec 13, 2011 8:10 am

Check pg 7-13 of the 2006 FSM (download a copy from the link on Sams NOOB guide if you don't have one). Joe is correct this applies to the electric fan on the gas engine but the setup is the same for the diesel. They were lazy with the cooling diagnostic section and only did diesel specific language if there was a difference between gas and diesel symptoms/diagnostics.

You may have to go to the wiring sections to locate the items referred to in #1 and 2.

cxturboboost · **Posted:** Tue Dec 13, 2011 9:48 pm

Can someone tell me where the fan control sensors are? That is the #1 on the list.... I've already checked the solenoid by swapping one of the others... It's fine...

Just need to find the sensor?

Thanks!

Pete

Joe Romas · **Posted:** Wed Dec 14, 2011 8:09 am

cxturboboost wrote:

Can someone tell me where the fan control sensors are? That is the #1 on the list.... I've already checked the solenoid by swapping one of the others... It's fine...

Just need to find the sensor?

Thanks!

Pete

I checked the FSM and could only find one sensor and it's in about the center front to back on the driver's side (US) of the cylinder head :SOMBRERO:

Have you checked good the wire bundle on the rear of the engine as it goes behind the fuel filter head bracket?

cxturboboost · **Posted:** Wed Dec 14, 2011 9:39 am

Hi Joe,

I'm assuming that's the sensor that also ties into the temp gauge. It is working fine so I would be confused to if it would be the problem?

I'll check wiring loom tonight...

Pete

papaindigo · **Posted:** Wed Dec 14, 2011 10:41 am

What Joe is referring to sounds like the coolant temp sensor on the back side of the tstat which I "think" only relates to the dash temp gauge but I have not checked the FSM electrical charts which I can barely understand. What may be the problem is a faulty AC high pressure switch (see pg 24-41 of the 2006 FSM). I strongly doubt that this is a KJ CRD specific issue but rather a KJ AC issue that any competent AC shop should be able to diagnose and fix.

Joe Romas · **Posted:** Wed Dec 14, 2011 6:01 pm

papaindigo wrote:

What Joe is referring to sounds like the coolant temp sensor on the back side of the tstat which I "think" only relates to the dash temp gauge but I have not checked the FSM electrical charts which I can barely understand. What may be the problem is a faulty AC high pressure switch (see pg 24-41 of the 2006 FSM). I strongly doubt that this is a KJ CRD specific issue but rather a KJ AC issue that any competent AC shop should be able to diagnose and fix.

NOOP! Look at the parts fich, section 08 under electrical, figure 8-615, item #18. It's called a "SENSOR, temperature sending" and is part number 05066779AA :SOMBRERO:

I suspect the wire for it is in the bundle that passes behind the fuel head.

And it's exactly where I said it was. Driver's side, in the US, of the cylinder head about half way back. The FSM shows it in one of the pictures but does not say anything about it.

He can eliminate the AC high side sensor by removing the plug from it :mrgreen:

papaindigo · **Posted:** Thu Dec 15, 2011 8:30 am

I see that sensor on the referenced pg of the 2005 parts fiche although I think it's actually item 17 (18 appears to be an air flow sensor) and for what it's worth there is a slightly better indication of location on Figure 2.8L-210 of the 2006 parts fiche as item 35 - both have the same part #. Assuming a wire plugs into that sensor then I'd guess if pulling that wire on a cold engine stops the fan then the sensor is bad.

Good suggestion on how to check the high side switch.

My bottom line remains more or less the same unless there is something actually overheating (easy to tell - on a cold engine/AC off turn the ignition key on; if that fan runs immediately then it's not an overheating problem) then the problem is likely a bad sensor of some sort although a stuck relay is not impossible. I'm just good enough to find that fan in the FSM electrical diagrams but not nearly good enough to figure out what sensors send a signal to turn it on/off. In wandering thru the 2006 FSM I just noted codes P0480 and P0481 which appear to relate to malfunction of that fan but there is no information on what sensors are involved. That said it occurs to me to bring back up my earlier comment on the power distribution relays. Have you tried pulling them one at a time to see if removal of a single relay stops the fan or if you have to remove both? If removal of just one stops the fan try replacing that relay with the other fan relay; if the fan does not run then the relay you pulled would appear to be stuck on. If the fan runs with the swapped in relay or if you have to pull both relays to stop the fan IMHO it's back to a bad sensor unless, I hope not, there is a problem inside the module that signals the relays.

FYI I had this exact problem years ago on a Plymoth Voyager although I, unfortunately, don't remember the cause. I do remember it was a simple and inexpensive dealer fix.

Best I can do, good luck and please post what the solution was for future reference.

Joe Romas · **Posted:** Thu Dec 15, 2011 9:37 am

I forgot to mention, I was referring to the 06 parts fich :JEEPIN:

That's what he and I have and the reference numbers I gave were correct. Also in the following I'm refering to the 2006 FSM.
On page 8W-30-18 it shows both the high and low radiator fan relays being directly operated by the ENGINE Control Module. So if you pull the 2 radiator fan relays one at a time (layout of PDC is on 8W-10-2) you can see what speed the fan is running on, high or low.
The pick circuit for the relays is provided with 12 volts through fuse16 in the PDC and the ECM supplies the ground to pick the relays. So if both relays are good and there's no wire shorted maybe by the fuel head then the signal telling the fan to run is coming from the ECM.

Page 8W-30-19 shows the engine coolant sensor connected to the ECM. I have no idea how the dash temperature guage get's it's information and can only speculate it's from the CAN bus.

Now what is causing the ECM to turn the fan on is the question :shock:

Looking at pages 8W-91-25 through 8W91-32, connector/ground/splice locations, I can not find anything that could be connected to sensor in question on the left side of the engine.

cxturboboost · **Posted:** Fri Dec 16, 2011 8:29 pm

OK...On the high side ac switch there are three pins.... None of them have continuity to each other... Would that be the problem? The service manual says to check both sides, but I've tried continuity to all pins and none exists?????

If I unplug the temperature sensor on the head the fan still stays on....If I unplug the high side ac switch, the fan still stays on....

Pete

Joe Romas · **Posted:** Sat Dec 17, 2011 1:23 pm

UPDATE!

I think your checking the wrong sensor. The high side switch is on the driver's side below the battery and at least the plug has three wires going to it.
24-44 shows the low side and 24-42 shows the high side.

According to what your saying your looking at page 24-41 of the FSM and you know the CRD has a switch and the gas burner has a transducer :BANANA:

Now turn to page 8W-42-7 They show a 3 leged transducer but give you the wiring for both the gas and diesel. It looks like you should have continiuty between both pins 1 and 2 to pin 3.
It says back on 24-41 if you have no continiuty then the switch is bad :shock:

The next page says the switch can be replaced without emptying the system :ROTFL:

Stores don't normally take electrical parts back but you could just plug it into your harness and find out if that's your problem.
I'm hesitant to tell you to jumper the pins because were dealing with solid state components and we don't want to let the blue smoke out :-)r

cxturboboost · **Posted:** Sun Dec 18, 2011 11:20 am

Hi Joe,

I am checking the High side A/C pressure switch down by the compressor. If you pull the connector off- the sensor itself has three gold pins coming up. If I check for continuity there is none between any of the pins.... Can you check yours for me? Service manual is saying its bad, but I'm just not sure. I may be able to do as you have said and order one and just try plugging it in before install?

Pete

Joe Romas · **Posted:** Wed Dec 21, 2011 1:36 pm

Pete.

Any progress? I tried to remove the plug on my high side sensor but stopped short of breaking it. I have a fond dislike for these darned retaining clips :furious:

Joe

Electrical fan runs constant and glow plug indicator quit...

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