lower sender temp unit afterrun..... not working?

[S4]

hello,

I have fitted the correct sender unit and did not notice any extra pump noise or anything?

the only fan that runs is the Normal fan on the rear of the rad passenger side.

when I put the A/C on both fans run, IE the one on the front, and the rear drivers side one.


I have removed the green multiplug that goes into the new sender unit, and tried bridging this, I here no pump and no fans run, that is with the ignition on and the engine running.

is there a fuse or any VGA tests I can do,


Thanks

Darren

[Blue_Thunder]

You won't hear the pump running with the engine on!

Try bridging the connector with the engine and ignition off, to mimic how the after run pump mod works.

[S4]

ok Blue, it must sent a live to the fan and the pump, when (0) ignition off... ill give it a go.

Darren

[daybar]

I have the same as S4. I've just been out to bridge the connector with ignition off and nothing happens, so it seems no power is going to the sender.

[dest]

Ive just fitted mine, and after a drive to get it up to temp couldnt hear anything running after parking up.
Temp gauge showing 90 when I stopped, it never goes above that!
I remember reading the new sensor kicks in at 93?

[Nige_RS4]

Ive just fitted mine, and after a drive to get it up to temp couldnt hear anything running after parking up.
Temp gauge showing 90 when I stopped, it never goes above that!
I remember reading the new sensor kicks in at 93?

The temp gauge is set to show 90 degs between quite a wide temp variation, something like 85-95 IIRC. It should kick in every trip if you've updated the after-run temp sensor (nor the G62 temp sensor).

[dest]

I got the after-run mod from Vagparts

[tdiquattro]

Are either of the 2 electric fans running at all - when the engine is hot / ac on etc?

The fans and pump are controlled by an electronic module in the engine bay, lately it seems these are packing up, dunno if thats your problem, the first thing to check is the fuses to the module - under the drivers footwell cover on the 8 way relay block at the back - 19 (40A) fan feed and 21 (5A) control module feed.

Bad news is a new module is £100, there are a couple on ebay for £50 at the mo tho.

[dest]

Ive just been out for a drive and got it up to temp, idling after a run it sits at 90 and never goes any higher.
The fan didnt kick in, and there is no fan when the aircon is on either!
I will check the fuses when (if!) it stops raining, hopefully it is one of those

[dest]

Checked the fuses, I found a 5A, 50A and 60A but no 40?
They were all ok, so tried bridging the connector to the sender with the engine/ignition off, and got nothing then too

[daybar]

I've still got this problem and have ordered a new afterrun pump. I get battery voltage at the sender immediately after turning the engine off (no need to warm it up, just start it and switch off) and all my electric fans run at some time or other except when the ignition is turned off.

So my analysis (could be wrong of course) based on this and the afterrun pump section of the self study guide 198 - pages 10/14 - is that the ecu sends voltage to the sender for (probably) 10 minutes after switching off the ignition. If the sender says it's hot enough to need the afterrun pump, the ecu/fan control module switches on the pump and one of the electric fans (the latter at 40% full speed according to the self study guide and perhaps dependent on the pump starting) and it all turns off 10 minutes later. If you test for battery voltage more than 10 minutes after switch off, you'll find none and there's none while the engine is running.

My problem could be the fan control module Nige mentions but the pump is a bit cheaper to replace as a first resort and they don't have a good reputation for reliabilility. If it is the fan control module, mine would seem to be only partially broken because the electric fans do still work, but I haven't checked to see if they display the full repertoire of speeds that the SSG mentions.