STUCK ON: radiator fan, fuel gauge, water in fuel light

KeighJeigh · **Posted:** Sat Mar 19, 2011 10:03 pm

Related or coincidence?

I finally have some time with my son to take a short trip over mountains to the family cabin. Incredible snowstorm last night we were the last ones over the pass before it was closed . . . Very glad to have the CRD.

EXCEPT, when I stopped for fuel I noticed the cooling fan was on. But we were heading downhill, it was in the lower 30s & verything else in the cooling system appeared ok. The guage shows a tick left of center - where it always is.. . . And yet the fan was on high.
It's in the upper 30s today with very light loading on the engine and 50mph hwys I've driven many times. . . but it has remained on all day. It won't go off even if the car is dead cold and just the key is on. So, I pulled the fuse.

Is it safe to assume this is a sensor issue? If so, is it controlled by the one connected near/on the thermostat housing? Or is it a separate controller somewhere?

Meanwhile, I'm apparently getting 150 mpg because the fuel guage hasn't moved off of 'full' the whole trip. It's not cold enough to be iced up. Is it a matter of taking it on a bumpy road when nearly empty to shake the sensor loose or perhaps just buy a new one? Similar to the fan issue; is there some controller/interface system involved here or is it most likely just the tank sending unit?

I also had my water-in-fuel light come on last night. I thought it could possibly be related to the gasket on the stock filter bulging out (First time I've seen this happen & it's not overtightened) and subsequent fuel dribbling onto the water sensor plug on the bottom. However, I took everything apart, cleaned & dried. . .but the red light persists. I tried clearing codes as well to no avail. (i don't actually see a code for this, however.)

Logically, these would not appear to be related issues . . . but geez, I dunno. I'm about to head over the pass & home. I've visually checked what I can, but must admit I don't like that nagging feeling that something is amiss with my car & I could end up stranded along a dark mountain pass hwy in the cold with a 5 year old.

I still haven't figured

racertracer · **Posted:** Sun Mar 20, 2011 9:25 am

Why don't you try rebooting the system by pulling the +positive terminal off the battery for 5 minutes and letting the ECM reset itself, and see if that doesn't solve it.

On another note, does your cooling system need flushing? How many miles do you have on your coolant?

KeighJeigh · **Posted:** Sun Mar 20, 2011 4:59 pm

Thanks! I will try rebooting. Although...... I checked and there are no codes associated with any if these problems and I don't think they are all tied in to the ECM.

I've flushed the radiator numerous times - especially during my quest to find an overheating issue last year - which I did.
But the temp guage is working fine; one tick to the left if center as always. More importantly, the fan won't ever shut off - even when I started it up in feezing temps in the morning with a stone cold engine. It's on constantly no matter what the condition.

papaindigo · **Posted:** Sun Mar 20, 2011 5:41 pm

Check pg 349 of your 2005 Owners Manual for relay locations and pg 7-13 of the 06 FSM for diagnosis, yes I know that's for the gas engine but the logic is the same and there is no equivalent diesel discussion. My past experiece, different vehicle though, with the fan always on symptom was a failed fan relay (the sensor on the tstat runs the temp gauge and might, I don't know, also link to the fan via a relay but since your temp gauge reads fine I'm betting it's a relay). The fan is 2 speed with the speeds controlled by 2 different relays (R34=hi and R40=lw). A member that knows more about electrical systems than I might have a better idea but if the 2 relays are identical, you may be able to tell by their labeling, then you might be able to check for a stuck relay by seeing which relay you need to pull to kill the fan and them plug the other relay into that slot. If the fan does not come on then the pulled relay is probably bad and you should be able to plug it into the other slot which will turn the fan back on if the relay is stuck.

Your other 2 symptoms would appear to be unrelated but then I'm no post-1975 car electrical system expert.

Joe Romas · **Posted:** Sun Mar 20, 2011 6:03 pm

Turn your heater off first and see what happens :jester:

In the heat position the AC comes on to dehumidify the cabin air and that may be why the fan is running :JEEPIN:

So if the heater is causing the fan to run then it's normal. Even bi-level runs the AC :BANANA:

KeighJeigh · **Posted:** Tue Mar 22, 2011 3:39 am

Reset the batt twice, cleaned & checked the fuel manager including the watwr in fyel sensor no diff. I'm also letting my tank go very low in hopes of jogging lose what I assume is a stick sensor.

For the rad blower i turned everything on, off, cold, hot, checked both relays & they work fine. So.... I assume it's a sensor problem.........which is located....on the thermostat??

I have no idea,why the fuel in water is on. I clean it carefully.

And just to ad to my sensor problems, I've gotten several incidinces of oil pressur lamp comming on. Oil level is fine and I've already replaced the oil sensor last fall.............??

papaindigo · **Posted:** Tue Mar 22, 2011 8:17 am

Just a thought since you appear to be chasing several odd electical problems; most everything is computer driven and a weak battery can produce some very odd symptoms. It might be worth having the battery load tested to see if perhaps you have a bad cell.

KeighJeigh · **Posted:** Tue Mar 22, 2011 9:42 pm

Optima battery . . . and fairly new. Voltage is fine both loaded & unloaded, it holds charge, car starts no prob in cold weather.

HOWEVER, you make me wonder if this might be related another unsolved electrical mystery I discussed in another post: The case of the pulsing lights! Under certain conditions, the lights pulse 3-4 times/second - usually around 1500 rpm but other times just at idle when I load the system. . . Or just lightly accelerate. That is a weird one I have yet to figure out. But perhaps........that occassional variation in voltage is throwing something off??
Note: I also tried unplugging the ecm hoping it might reboot but it's the same as pulling the battery cable (duh. At this point I'm just scatter gunning)

changingtime · **Posted:** Wed Mar 23, 2011 8:22 pm

actually to reboot the system and to get any stored codes out...pulling from memory from what the dealer told me.

you actually have to touch the postive and negative battery cables together. BUT first, if i recall, unplug the ecm, tcm and ABS computer. this gets all codes out of memory stuck in the capaciters.

KeighJeigh · **Posted:** Thu Mar 24, 2011 2:07 am

That might do it....and I would try right away...except that you sound a bit hesitant.

Anyone else tried this??

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STUCK ON: radiator fan, fuel gauge, water in fuel light

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