Hi all,

 

Bought my car with 25K in November 2014, it has now done 75K, its been fairly reliable (one issue Water pump (and also cambelt as part of the process) replaced under warranty.

 

However this new problem is starting to really frustrate.

 

1) The blower motor resistor packed up - I replaced it.

 

2) Blower Motor resistor packed again

 

3) Garage replaced it, blew again, blower itself motor had packed up.

 

4) Garage replaced blower motor, resistor, pollen filter and fuse. Worked for about 24 hours. Puff of smoke another resistor failed. 

 

5)Garage had car back in, fitted higher rated fuse and new resistor fuse - worked for about 6 hours, basically until I next used the car. 

 

6)Currently have no fan at all (not even on just setting 4).

 

I have seen various comments alluding to wiring harness issues, but cannot find any details on how to fix. So I would be very grateful for any useful suggestions... The system the car has the basic heating / air con system - 4 setting fan control.

I'm amazed that the garage would fit a bigger fuse.  That could lead to a wiring fire.

 

It might be worth running a quick and simple test to see if the alternator's voltage regulator is functioning properly, and is not putting out too high a voltage that could be responsible for frying sensitive components.

 

Hook up a voltmeter across the battery terminals.  All electrics off.  Start the motor and increase the revs until the voltage on the meter remains steady.  Should be not less than 12V and, more important for this case, not more than 14V.  Repeat with all electrics on e.g. lights, rear window heater etc. -  results should be the same.

I'm amazed that the garage would fit a bigger fuse.  That could lead to a wiring fire.

 

It might be worth running a quick and simple test to see if the alternator's voltage regulator is functioning properly, and is not putting out too high a voltage that could be responsible for frying sensitive components.

 

Hook up a voltmeter across the battery terminals.  All electrics off.  Start the motor and increase the revs until the voltage on the meter remains steady.  Should be not less than 12V and, more important for this case, not more than 14V.  Repeat with all electrics on e.g. lights, rear window heater etc. -  results should be the same.

 

more than 14V is quite common, in most cases you should get around 14.2V and if you were only getting 13V I would consider that a low output, if your only getting 12V the battery would not be getting charged

Edited 4 April, 201610 yr by SuperbTWM

Quite right SuperbTWM, I stand corrected.

I would check the wiring to the fan and the connections where it meets the fan and also at the fuse end an earth point. If you have a bad connection the current draw will increase and extra current going through the fan is going to damage it and the resistor pack and also possibly the 5 position switch in the dash.

I would check the wiring to the fan and the connections where it meets the fan and also at the fuse end an earth point. If you have a bad connection the current draw will increase and extra current going through the fan is going to damage it and the resistor pack and also possibly the 5 position switch in the dash.

A bad connection would increase resistance, therefore reducing current in the circuit.

I=V/R

I- current

V- volts

R- resistance

Double resistance = half the current

A bad connection would increase resistance, therefore reducing current in the circuit.

I=V/R

I- current

V- volts

R- resistance

Double resistance = half the current

Sorry, yes your right.

 

But something is causing a high current to be drawn otherwise the fuse wouldn't have blown, unless the failure of the fan caused a short.

Edited 4 April, 201610 yr by SuperbTWM

An electric fan will draw maximum current when it is stalled.

http://robotics.stackexchange.com/questions/613/what-is-stall-current-and-free-current-of-motors

Maybe the fan is getting jammed & the circuit can't cope.

Thanks all, will start investigations at the weekend. Also found on this article;

 

'Individual climate controls may not work properly. A chafed cable shows up on the OBD II diagnostics as a faulty control panel. Worth knowing because the control panel is £300. Confirmed by another reader. The cable chafes between the engine bulkhead and the dashboard causing an intermittent short' http://www.honestjohn.co.uk/carbycar/skoda/octavia-2004/?section=good

 

Does that make any sense?

 

Thanks again, really appreciate the comments and help.

 

R