So i noticed that my temp would go up when i had the a.c on and thought nothing of it until it went way up today. I took the front grill off to see if the fans were working and found they were not on. I took a jumper from the battery to the fan and nothing. do they have a thermostat inside of them of are they dead??


Thanks,

Walter

 

Quit driving it with the a/c on and in hot weather till you get them replaced or you will toast your motor.
As to your question, no, they do not have an internal t/stat so plan on locating a new or used set.

 

I very rarely use my a/c. i work out side and if i get in the truck and turn the a/c on and go to another job site it makes it seem twice as hot. but the other half hates the wind and prefers a/c.

 

well I got one for sale on ebay!

http://cgi.ebay.com/ebaymotors/ws/eB...#ht_500wt_1182

 

Doesn't your D1 have a dual fan set up? I believe only D2's have the single fan.

 

yep it has 2 fans

 

AC Condenser Fan aka "Aux Fan" / 'Auxiliary Fan': Troubleshooting, Removal, Repair

2004 Land Rover Discovery SE

Newbs: fan location = front most of truck, directly behind the front grille. It cools the air conditioning (AC) condenser (the front most 'radiator' looking thing). There are two fans. This is not the 'clutch fan' which is run by the serpentine belt at the front of the engine which cools the engine coolant radiator, located just behind the front most AC condenser unit. The AC condenser fan, the aka 'aux' fan, is bolted to the front of the AC condenser.


Troubleshooting:

Observable facts on my truck:

• (1) AC condenser fan NOT turning on with AC
• (2) 40amp fuse is blown (the fuse labeled "F5" in engine bay fuse compartment).

In my case, all relevant fuses/relays are located in the engine bay compartment fuse block located above the front passenger-side wheel



I. Try a new fuse first. Pulled blown fuse, installed a replacement 40amp fuse to the F5 fuse socket which protects the AC condenser fan circuit. Since ECU has specific temp / drive cycle parameters as to when AC condenser fan activates (? Does it >>HAVE TO<< go on w/ the AC? ... I don't know that for a fact.), inconclusive after driving around w/ AC 'for a while' under summer conditions.

Result: after driving around* w/ AC on, new replacement fuse was intact, not blown. {*re 'driving around': Wanted to make sure it's getting airflow since ?no condenser fan? No idle driveway testing since probably ZERO fan cooling to AC condenser}.

Tentative conclusion: seemingly, AC condenser fan is NEVER activating under any circumstances (?), but let's make certain that's a true statement.
Likely scenario: probably fan is toast, but I don't know that. Good techs don't like words such as "seemingly" since it could be a wiring problem somewhere in the device's electrical circuit.

II. So, since replacement fuse test not blowing immediately / no 'smoking gun', I figure let's bypass the ECU which controls the AC condenser fan activation per specific temp and drive cycle (heat) parameters. Methodology: let's use the Dr.'s office rubber mallet to strike the knee tendon (relay socket) and see if the foot moves (fan spins up) w/o the brain (ECU) being involved. The R4 relay socket is the best place to test since it has the 'most "central" strategic position' within the entire fan activation circuit.

To do this, let's activate the relay manually (relay "R4" in the engine compartment) and see if the fan runs.

How? Use a test jumper or wire bridge applied to the R4 relay. The jumper test wire is itself fitted with a 40amp fuse per best practices / common sense.

Jumper test wire setup: Looking at the pins on the relay itself, I know the magnetic induction or mini-coil relay 'trigger circuit' in the relay itself are pin sockets 1 and 2 per industry standards -- so I DO NOT want to jump those pins since it's the trigger circuit, not the device (fan) circuit, per industry agreement. The other set of pins on the relay which are in the 'load' or 'switch' or 'device' circuit (in this case, the AC condenser fan), are pins 3 to 5 as they are on all "ISO style" relays (or, equivalently, pins 87 - 30 on a "Bosch style" relay). So, I know that THESE pin sockets -- 3 to 5 -- are the pin sockets in the fusebox array that I want to carefully and thoughtfully 'jump' or 'bridge together' for testing.

Test: Relay R4 removed pulled from truck and set aside. W/ truck running, applied an in-line 40amp fuse jumper wire to relay R4, specifically, sockets 3 - 5 (which correspond precisely exactly to pins 3 and 5 on the relay module itself). Caution here. Go slow, be careful, THINK through exactly what you are doing -- or don't do it.

(So, to my knowledge, my jumper is simulating a closed aux fan (condenser fan) trigger circuit, namely, it is a stand-in for the magnetic induction of relay pins 1 and 2 ... I'm forcing the trigger, relay pins 1 - 2 to a closed position. I'm manually closing the device (aux fan) activation circuit, I'm the trigger instead of waiting until the ECU takes it's sweet time to activate this circuit per it's pre-programmed parameters (a certain temp, a certain drive cycle state, ... ). My jumper IS a closed, activated relay trigger doing it's job when it finally gets called out by the ECU at high temp and/or w/ the AC on or ?. I don't care about all that now. Point is, I'm not just waiting around for the ECU to decide to do it's thing and activate the relay. I wanna know right now what the deal is with the AC condenser fan!. Worky or no worky? No one taught me this. I simply thought about it)

Test Result: w/ truck running, 40amp in-line fuse jumper wire across relay R4 pin sockets 3 - 5 .... drum roll ... the jumper wire fuse blew instantly.

OK. Slowly drawing the net tighter here. So now I know for certain it's either a WIRING short-circuit in the wires of the device circuit of the AC condenser fan, OR, it's a short-to-ground inside the fan motor itself. It can't be anything else.

I surmise (hope) it's the fan motor that's blown, since I don't want to mess w/ a wiring harness. But I don't know that for sure. So? More testing...

Bright idea: Remove the fan from the truck**, determine how many volts it needs to run, and bench test it.

Why? This is the fastest, smoothest, least error-prone path forward. It's foolish to start fiddling with wiring harnesses w/o a very good reason. Testing connectors, wires, switches and the like is a last resort since the testing process itself could damage wiring and then other unrelated devices could start having problems. Go there last, only if you must. So, I go to the physical fan motor itself first for testing.

So let's focus on the device -- the fan motor. I know the fan requires 12v to run. If, when sitting on the test bench, the fan starts spinning and runs perfectly fine when applying 12v directly to the fan's two wire connector, then I know it's not the fan motor that's shorting out, it's instead the wiring in the fan circuit causing the fuse to blow. If however the fan, when connected directly to a 12v source, immediately blows the in-line fuse in the benchtest jumper test leads, then I KNOW it's the fan motor causing the short. Easy. Simple. Logical.

Result: Test fuse blows instantly when fan is bench tested @ 12v

OK. It's the fan. I KNOW this now, I'm not guessing. I lookup the fan online. OEM, new, it's $700+ USD in (inflated) 2024 dollars. Ugh. URO Parts has one for $250 and change. I order a new $250 fan, since I'm not a fan of spending $700+ USD on a fan. URO parts = ?, but that's OK (?), there's some of their stuff on the truck and it seems mid to OK. A fan's internal componentry is simple after all, trivial, just a motor with brushes etc. like my cordless drill, so, no worries. How bad can they mess it up? I'm happy to save $500 and change. I now KNOW that a new fan will fix the problem. I'll open up the original fan at my leisure to see if I can fix it, or if I don't have the time or energy, I won't. I have options now, before I just had a fan in a questionable state of worky? / no worky?. Is there an off chance there's more to this? Yes, of course, but that's ceteris parabus: you can always say that. But is it likely? No, it's not likely. My tests point entirely to the fan motor being shorted out. These tests didn't take long and were definitive.

So: I thought it was a short to ground in the the fan, turned out it was in fact a short to ground in the the fan motor, it was not a problem with the truck wiring circuit which goes to the ECU on one side and terminates at the fan on the other. Great. I resisted the urge to be a mindless parts changer. I feel good about that. BTW I did the same thing with the starter not too long ago. In that case, again, it was an internal device fault in the cranking motor (starter) as I suspected, but I proved it first by removing the starter and bench testing it.

If you're in a pinch, I totally get it, you can gamble and just swap out the part, but what are you going to do when it IS a tricky subtle wiring problem? As a parts swapper, you won't have the means to test that you've developed by simply being methodical and thorough (granted, this 'thoroughness' equals both $ and time, two very precious commodities, and can be overdone at repair $hops and often is. ...IMHO, it's the same thing in the medical industry. Thoroughness, testing and more testing to a fault ($$$), and not thinking broadly and simply about what the high probability likely problem areas are and proceeding accordingly).

Bottom line, you need to have a quick way of confirming / dis-confirming whether the component or the wiring is at fault. This is often done at the relay, that is, the 'crossroads' of the both the trigger and device circuits. So, if nothing else, at a minimum, if you dig into this even a little bit, you are well on your way to accurately troubleshooting issues on any vehicle w/ your lights, your horn, your radio, your fan, and your starter(!)), and your shop of choice can't sell you the Brooklyn Bridge over something comparatively simple and obvious because you've at least vetted things out a bit and have a decent idea of what's going on. This isn't difficult, and it's worth your time. Preaching to the choir I know, but this is vital info, esp. for newbs. More broadly, these are questions every enthusiast should ask if they are serious about keeping their beloved Disco rolling.

Peace.

Take your time. Don't be a caveman.

I welcome any constructive criticism to the above effort. Thanks to all who have contributed to this forum which has saved my bacon many times. THANK YOU.

~~~~~

Addendum:

**AC condenser fan removal notes:

After taking off the grill, watch that the plastic grommets on the fasteners don't fall away into the front of the truck as you're pulling away the grill. I heard that happened to a guy somehow somewheres once a while back .

Pre-soak the fan frame fasteners -- (4) 8mm bolts -- with a penetrating oil such as PB Blaster. Threads of mine were nicely rusted / crusted. (These four fan frame bolts are also phillips head (posidrive), but they are useless/inaccessible as such -- even with a right-angle phillips driver -- it's far too cramped in this space to get a good bite on the these small crusty fasteners with a screwdriver.)

When you're facing the truck, the UPPER RIGHT 8mm bolt on the AC condenser fan is hopelessly buried behind the hood latch receiver body -- it's quite happy in its hidey hole, and it hates you. So, you need an 8mm ratcheting box-end wrench to get at it. No problem at all w/ the right tool.

Use a 1/4" ratchet fitted w/ an 8mm 6 point socket for the remaining three bolts. Use a swivel (aka "universal joint") on a 2" or so extension since you can't get straight at any of these three bolts (upper left, two on the bottom). Put duct tape or gorilla tape around the swivel so it doesn't flop around in blatant display of rebellion and uselessness. Tame that swivel.

Remove one of the crossbars bolts on one of the crossbars and push the crossbar it aside to open up a gap through which the fan can be removed from the truck. Don't lose the crossbar bolt. Mine dropped into the front bumper. Magnetic telescopic grabber tools are both cheap and awesome.

Re the fan 12v connector, slide a small flathead screwdriver under the bow of the connector interface to depress the tab on the connector body, and it will easily slide apart. Bench test the fan.


LRD2 AC condenser (aux fan) relay socket test for short to ground



Aux fan removal / testing: these are your friends

UPDATE: After replacing AUX fan, it is now clear that the original has been blown for ages -- bench tested, confirmed shorted to ground -- and that the aux fan is active 100% of the time the AC is ON, and that the replacement fan, a URO, @ $250, is of inferior build quality to the original @ $750, but it's working fine and I am grateful for the $500 savings... It having been out of operation for such a long time, any reference above to the ECU making executive decisions as to when or when to not activate the fan is purely d/t my wooly-mindedness and never properly observing its default operation: Now I know via observation that the AUX fan activates: 1) 100% of the time the AC is on 2) Engine temps above 212F Thank you to the veterans here who know all this stuff cold.