Section : Electrical Equipment

Alternators, dynamos, lights, wipers, etc.

Variable speed indicators

Posted By : Alan Madin, 10-Nov-2006, 08:51am

Have now done a few hundred miles in my 'new' MK IV and am getting to know the glitches.
Question is why does my indicator speed vary with engine revs?
Problem is not there at above 2000 revs but at idle speed right indicator is 'on' or flashes very intermittently, left is a very slow flash.
I know simple answer is replace the flasher unit but, before I go there, could there be a more serious problem hiding in the wiring etc??

Thanks
Al

Followups :

Variable speed indicators

Posted By : Garth Jupp, 10-Nov-2006, 09:06am

Alan,
I would check the earth returns for all the indicators as bad earths can cause this problem.

Garth
- Variable speed indicators
  
  Posted By : Chris Mills, 10-Nov-2006, 09:31am
  
  Alan
  
  Might also be worth checking and cleaning the steering rack's earth connection in the engine bay as the steering column is earthed throu this as well.
  
  Cheers
- Variable speed indicators
  
  Posted By : Michael Charlton, 10-Nov-2006, 12:17pm
  
  I agree with the earth scenario but also check the can is correct. When I first got my car , the can was the size of a wheely bin and the wrong rating and gave exact symptoms as yours . Changed it and its worked correct ever since
  Mike
  - Variable speed indicators
    
    Posted By : Chris Taylor, 11-Nov-2006, 00:14am
    
    I'm not sure the indicators are earthed through the steering rack, but if that is the problem then more hesitant or intermittent operation of the horn would be a clue. I'd also check the battery and charging circuit (are the headlights dimmer or subject to a sort of flicker at low revs?) Increasing voltage at the battery as the alternator charge increases would give the symptoms you describe.
    - Variable speed indicators
      
      Posted By : Alan Madin, 16-Nov-2006, 04:01pm
      
      Have started looking by quikly going under 'dashboard' first. Have given connections a bit of a twiddle (non technical electrical term!!) etc and it seems to be improved so will follow up properly later - other commitments have prevented me getting stuck in properly - but this weekend......
      So thanks for advice and I will work my way through it!
      Cheers
      Al
      - Variable speed indicators
        
        Posted By : Paul Bodiam, 16-Nov-2006, 11:17pm
        
        Hi Alan
        
        As has been stated earlier in this thread, the speed changes because the flasher speed is directly related to battery voltage (which varies between about 11V and 14V depending on engine speed and electrical load). It will be worst on a cold wet evening when you are using headlights, heater fan, and wipers. The indicators may stop flashing altogether when you pull up to a junction. This is not so good.
        
        It is possible (and easy) to replace the old electro-mechnical flasher relay with a modern electronic one. These modern devices are not sensitive to supply voltage. Have a look at this thread:
        
        http://www.tssc.org.uk/messageboard.asp?board=spit...
        
        cheers
        Paul
        
        Variable speed indicators
        
        Posted By : Philip Brammer, 18-Nov-2006, 01:11pm
        
        Many thanks for that Paul, I've been struggling with this since I decided to use the old girl (car that is!) during the winter. Replaced the old unit with a new 'solid state' one and its cured the problem! Hurrah! And I can now hear the indicators ticking! Can't say which one it is as the guy in Halfords just gave me a large box full of different units to look through and I picked the one that looked the friendliest.