bofus Posted February 9, 2010 Report Posted February 9, 2010 here goes....freshly refurbished heater (Polish Ebay company - no problems with unit and as delivered). 12 months on the glow plug fails...lots of smoke...error codes...glow plug changed, clear codes...lots of smoke till the unit clears all the crud off.....then perfect for 6 weeks. Car then doesn't get driven for 5 weeks as I am out of the country, battery is flat flat on my return, gave it a charge and all is okay again......except that the aux heater is now not 100% Symptom 1 - Doesn't always turn on when it is cold - same issue you get if the car is standing for a while and engine heat triggers the ambient temp switch under the wipers.....but this doesn't clear when you drive for a while. Symptom 2 - Heater starts it cycle but turns off after 3 mins.....then Symptom 3 - Sometimes it just cycles over and over and over again during the journey. Symptom 4 - no error codes are stored! So, the questions are....... Is it possible to get air locks in the fuel line? Does the ECU for the car turn the Aux heater off when the fuel level gets low? the reason for the fuel question is...I filled up tonight and the heater fired on the second attempt, and ran with no smoke until i got home 10 mins later. The fact there were no clouds of smoke I assume that the unit hadn't filled with neat diesel! cheersGav Quote
Seatdriver Posted February 9, 2010 Report Posted February 9, 2010 (edited) Hi Suspect that if you get low fuel warning the Aux heater gets switched off. Mine fired up on the drive when first starting car in the morning but then I got the warning low fuel and next thing i could hear the Aux heater slowing down. Sure enough arrived at garage, filled up with diesel and as I pulled out of the garage away went the Aux heater. So I think yes it does get switched off, makes sense really. If youre low on fuel the less burned the better! Oh and I have noticed that the engine runs lumpy when the Aux heater runs. Done this on both of my cars. Mine however has started making a clicking sound when the engine is turned off and its obviously still been on full heat. Hey ho if mine goes wrong it will get permanently disconnected! Edited February 9, 2010 by Seatdriver Quote
Jayton Posted February 9, 2010 Report Posted February 9, 2010 Hey ho if mine goes wrong it will get permanently disconnected! Won't that add extra wear & tear to the engine because it's taking longer to warm up? or is it negligible? Quote
gregers Posted February 9, 2010 Report Posted February 9, 2010 sounds like the after run pump need a service,look in the faqs for very detailed instructions on how to carry out repairs,this is why i think the booster is spooling up/down.?? Quote
bofus Posted February 10, 2010 Author Report Posted February 10, 2010 run pump? If you mean the wate circulation pump.....this is new and works fine...if it isn't working you get no noise and a heater over temp warning. Or do you mean the dosing pump? Today.....it took about 6 /7 attmepts to fire and eventually got running after about 10 miles...tonight it fire up first time, got the water upto temp...then switched off and stayed off even when the water temp started to drop during the last 3 miles in traffic! argh!! Quote
Rusty Nail Posted February 10, 2010 Report Posted February 10, 2010 Is it just me or does everyone think that these Aux heaters are more trouble than there worth. Itr seens everyone has trouble with them at some point or other. Mine is working at the mo, but for how long is anyones guess... :-) Quote
gregers Posted February 10, 2010 Report Posted February 10, 2010 rusty,its that time of year again,suddenly the forum gets a glut of posts all to do with the aux booster heater,most of the questions have been asked before over the years. ;) Quote
Mirez Posted February 10, 2010 Report Posted February 10, 2010 Is it just me or does everyone think that these Aux heaters are more trouble than there worth. Itr seens everyone has trouble with them at some point or other. Mine is working at the mo, but for how long is anyones guess... :-) Nope! I've had very little trouble from both mine, just standard glow plug changes and the benefit is certainly worth that "hassle". To the problem though, since no faults are being logged I would be looking at the possibility of a faulty sender unit or wiring - either the coolent sensor or the air sensor. Use VagScope to monitor those two channels whilst you drive from cold and see what, if anything, occurs. Quote
bofus Posted February 15, 2010 Author Report Posted February 15, 2010 Tonights update! Over the weekend , I spent a couple of hours checking the ambient temp sensor, checking correct voltages around the heater etc etc. 12v main feed good, earth good. engine running signal good and when shorted out at the sensor plug, good signal to start the heater at the heater socket. Put it all back together, nothing! Checked the ambient sensor again, seemed okay..... external temp was around 5 deg so a few mins in the hand and it went open circuit, leave it for 10 mins and it closed. So this time I shorted the plug again, re-measured the heater socket, all good. Plugged it al back up and still nothing....VAG-COM was communicating okay though. The heater plug showed some fluffy corrosion around pin 6 (heater start signal from amb temp sensor), so I cleaned this and ....it fired up!...yippee...it went through a couple of high / low cycles all okay. It was now getting dark, so I plugged it all back as normal and went in. This morning...nothing! zilch! 14 miles to work and heater barely warm. So tonight, i have shorted out the ambient temp sensor, and so far three starts out of three goes! Watch this space! Quote
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