The first hot day here and and the tempgauge went to max in city stop and go traffic. When makeing speed the Arrow goes back to where it belongs. A/C works fine except the two relays are too hot to touch and electric fans only turn very slow.

I remember from when I repaired the A/C and had it recharged the fans turned on a much higher speed while ambient temperature only was some 10º.
Can I start with changing the relays to see if they are at fault?

The fans turn slowly .... is this on AUTO or by turning the control to the maximum?

Both fans at the same speed?

If you remove the pollen filters you can see the fans turning to get a better idea.

You could also swap the two yellow relays for two others in the fuse box.

Or are you talking about the condenser fans behind the radiator grille?

Sorry guys for not being specific, I was a bit in a hurry. It's the condenserfans I'm talking about., interiorfans blow as they should.

Relay 18 is getting very hot, reay 13 too, maybe because it's sitting next to 18. Looking at the diagrams relay 18 should serve the compressorclutch, which works.

Relay 13 serves realay 18 which in turn serves relay 14 which powers the right condenserfan (all powerfeeds, not the induction signals). The right condenserfan should come up when A/C is on I think but doesn't.

The left condenserfan is powered by fuse 31 in the fusebox, I can not trace it further back but I think it should kick in when enginetemp gets too high but it does not.
All relaysockets look clean and no traces of Sparks, relay housings are not discoloured.

Last thing that comes to mind on this very moment, when the A/C was recharged and all worked well (that is I heard fans and was too busy with cool air coming out of the dash) I had a spare manifold on the bench preparing for LPG, with a coolant temp sensor in it. Later I switched the complete manifold when ready and left the sensor where it was, maybe this can be a faulty sensor. Tomorrow I'll go to LR and buy a new one (€26, I can handle that).

If you have any ideas please throw them up.

Tony.

Hello Tony. According to ETM, when relay 18 is energised, it provides connection between relays 13 and 14 (fan 1 and 2) in series or parallel with each other. This is dependent upon the state of the air–conditioning pressure switch 1. <br>
Might be an idea to pull the relays and jump the fans individually to make sure the motors are good and work back from there? <br>
As an aside, your original problem was engine temp going to max in stop/ start traffic. Have you checked to see that your condenser and engine rads are clear of crap so that air can flow freely, your viscous clutch is engaging and actually spinning the fan with full force when hot and lastly, when was the water pump last changed? The impellers corrode away to just blades on the metal ones, and the plastic ones fall to bits! <br>
Even on our rare really hot days, coming straight from motorway speeds to half hour traffic jams, I've never actually heard my condenser fans kick in and the temp gauge stays happily at its 1mm above half (equating to 89-90 degrees on the Nano) where it sits all the rest of the time.

Thanks OB for your reply, yes the rads are free of crud, condenser is new prior to recharche (the old one had a leak) and I do not off road. Waterpump has a metal impeller, not LR but OEM I think, visually inspected it last january. When starting up from cold I can trace the temp rising in the heaterhoses within a minute so it pumps.

About the fans going parallel or not is determined by the dual pressureswitch X315 on the dryer if I understand you correctly? That one could be at fault too.
Jumpering relays is done by putting 12V to the pins 87 (87A), can I do that by pulling one at the time? I took out the relays and tested them by powering 86 and 85, they all clicked bravely.

High/low speed is indeed done by the dual pressure switch. The single pressure switch just turns the fans on/off (regardless of speed chosen). My single pressure switch is just bridged so whenever my A/C is on, the fans run. This isn't needed, nor under most circumstances will they ever actually come on, but I was troubleshooting another issue and have just left it that way. A bit of extra cooling can never hurt a V8...

By default they run at the low speed, where the fans are electrically connected in series through a pair of green 5 pin relays in the fusebox. I forget which numbers they are. They should only run on high speed (ie in parallel) if the pressure in the A/C gets silly high. I think in the case of an engine overheat, by the time the ECU requests they come on (at low speed too, I believe) its too late for the engine anyway...

When you say they are turning slowly, how slowly? Slow enough you can see the blades? If the relays are getting very hot and the fans are turning very slowly, it sounds like a poor connection inside one of the relays.

Hi Sloth, thanks for your reply. I switched the temp sensor with the old one (new one not until monday from dealer) just to try. Now both fans run slow (in series?), I will try to do the bridge trick with the single pressure switch and see if they go faster, this engine is getting really hot. Also will check the flow through the radiator, water poored in runs out quickly but that does not tell me if it follows the matrix or along the sides. After the weekend I'll post the result.

The single pressure switch doesn't change the speed - it only turns them on/off depending on A/C pressure. It is the dual pressure switch that determines speed. It will only switch the fans to run at the high speed setting if the pressure gets really high. With a properly working viscous fan, that should never really happen. The A/C fans themselves generally won't come on at all normally. The viscous fan does pretty much all the work cooling both engine and keeping the A/C pressures reasonable.

Even with the A/C on and on a hot day, if the engine is overheating, something is wrong somewhere. The A/C will negatively impact the engine cooling system because you're drawing hot air from the condenser over the radiator, but even so it should be able to manage just fine.

When you start the car from cold with the air conditioning on, do the fans come on immediately?

No they don't. This afternoon I watched closely when starting up from cold and A/C on, I did the bridgetrick on the single switch and they started turning calm, removed the bridge and they stopped. After a few minutes when the A/C cooled the interior well they came on by themselves.
I heard them go fast one time for a few seconds, that was on initial try after the recharche of the system, maybe the fluid had to level through the system.

What still puzzles me, the (left I think) fan that has to come by when the engine overheats does not come by. Whatever cause it is, when the arrow of the gauge goes into red I want a fan start turning (if it is designed that way).

Tony- I'm wondering if the condenser fan issue is a bit of a red herring. As Sloth says, by the time they kick in for a hot engine it's usually very late. <br>
I'm still thinking that the root of your overheating lies elsewhere. You've had the cooling system drained to fit your LPG. Do you think it might be our old friend- a bleeding issue and that you have an air lock somewhere? <br>
If the "normal" cooling system is in good nick- free of air, stat behaving, circulating well and viscous fan locking at higher temps, it is more than adequate to keep the engine cool even on the hottest days in slow traffic that I've encountered. <br>
Not saying that your A/C fans don't have a problem, just that that might be a distraction from the main cause...