Electrics: 850: - Heater and high revs

chelle_belle · Mar 10th, 2020, 19:27

Hi all,

When i slide the slider button to turn my heater on, the revs jump up from tickover to around 1300rpm, this in turn is giving me rev hang on gear change, also once in a blue moon the heater will just cut out but restart if i turn the ignition off then on again, with the heater off tickover is fine and know rev hang,
The car has a good battery and air con multi plug is disconnected,
Any advice much appreaciated.

Craig.

ASt85 · Mar 11th, 2020, 08:54

It sounds as though the power transistor on the blower motor has failed, replacing is quite straight forward but it might be more economic in the long run to consider changing the blower motor for a low mileage or known good working one from a breaker.

Baffler · Mar 12th, 2020, 21:35

Also consider servicing the idle air control valve (sounds as though it's sticking when compensating the engine load), throttle butterfly valve and housing.

The electric side of the gnition switch is another possible candidate so make sure it's returning to position II after starting the engine. Replacement is recommended if no knowledge of it being replaced

Mar 10th, 2020, 19:27	#1
chelle_belle and Craig! Last Online: Apr 1st, 2024 06:25 Join Date: Jun 2007 Location: Manchester	Heater and high revs Hi all, When i slide the slider button to turn my heater on, the revs jump up from tickover to around 1300rpm, this in turn is giving me rev hang on gear change, also once in a blue moon the heater will just cut out but restart if i turn the ignition off then on again, with the heater off tickover is fine and know rev hang, The car has a good battery and air con multi plug is disconnected, Any advice much appreaciated. Craig. __________________ Michelle and Craig. 855 R 855 T-5

Mar 11th, 2020, 08:54	#2
ASt85 Premier Member Last Online: Today 13:29 Join Date: Aug 2010 Location: Walderslade....Kent	It sounds as though the power transistor on the blower motor has failed, replacing is quite straight forward but it might be more economic in the long run to consider changing the blower motor for a low mileage or known good working one from a breaker. __________________ The saddest moment is when the one who gave you the best memories....becomes a MEMORY V70 SE 2004 2.3L T5 Geartronic, C70 2005 2.0T Automatic, Sold 2.4l 20 Valve Automatic Torslander Sold 854 GLT 20v Auto

Mar 12th, 2020, 21:35	#3
Baffler Premier Member Last Online: Today 14:00 Join Date: Dec 2002 Location: Co. Limerick, Ireland	Also consider servicing the idle air control valve (sounds as though it's sticking when compensating the engine load), throttle butterfly valve and housing. The electric side of the gnition switch is another possible candidate so make sure it's returning to position II after starting the engine. Replacement is recommended if no knowledge of it being replaced __________________ Liam... '96 854 TDI SE, '99 V70 2.5D S, '05 C70 2.0T Collection, '05 S80 2.0T SE, '15 V70 D4 SE Lux Nav.

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