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Weird electrical problem with my Mondeo

Discussion in 'Motors' started by dirtychinchilla, Nov 17, 2012.

  1. dirtychinchilla

    Soldato

    Joined: May 2, 2011

    Posts: 7,442

    Location: Woking, Surrey

    Hey everyone,

    I've inherited a 1997 Mondeo TD and over the last couple of days have been trying to fit a new radio. I bought it from Halfords so in the end I went back there and this chap fixed it up for me (and somehow didn't charge me!!). While sorting it out he found a very strange problem...

    For some reason the voltage of the power supplying the radio (and I think the 12v cigarette lighter thing) began at 7V and crept up to about 11V. We never got to 12V because it took so long.

    Now, before I go to a garage, has anyone got any idea what the cause of this might be?!

    Thanks in advance,
    dirtychinchilla
     
  2. Tesla

    Capodecina

    Joined: Jan 19, 2003

    Posts: 17,391

    Location: Bristol, UK

    With or without engine running?
     
  3. MatteH Oxford

    Wise Guy

    Joined: Jul 26, 2010

    Posts: 1,337

    Location: Oxford City

    it seems odd if both circuits are low as they are fed from different fuses.
    I'd check the voltage at the fusebox supply in the glovebox and go from there presuming battery voltage is o.k.
     
  4. dirtychinchilla

    Soldato

    Joined: May 2, 2011

    Posts: 7,442

    Location: Woking, Surrey

    With the engine running.

    Hmm well it may have just been the radio circuit to be honest, I think he might have grounded it on the cigarette lighter...

    Hmm OK, no idea how to do that but I'll think about it!
     
  5. MatteH Oxford

    Wise Guy

    Joined: Jul 26, 2010

    Posts: 1,337

    Location: Oxford City

    There will be a big fat red wire going to the fuse box, touch your multimeter probe on the connector where it screws onto the fuse box. Should be above 12v

    I'll try to find a photo
     
  6. PhillyDee

    Capodecina

    Joined: Feb 12, 2007

    Posts: 14,168

    Location: South Shields

    Check the multimeter is reading right on the battery as well. Should really be 12.8V ish.
     
  7. baron02

    Gangster

    Joined: Aug 8, 2009

    Posts: 456

    Location: Canterbury,Kent

    If this is a Mk3 mondeo these have a smart charge circuit.

    but head over to www.talkford.com as these guys will help you there
     
  8. MatteH Oxford

    Wise Guy

    Joined: Jul 26, 2010

    Posts: 1,337

    Location: Oxford City

    thinking about it, if he grounded it on the cig lighter it may have a slightly duff earth. I'd recheck the voltage using a different earth point for the negative probe.
     
  9. MatteH Oxford

    Wise Guy

    Joined: Jul 26, 2010

    Posts: 1,337

    Location: Oxford City

    it's a either a mk1/mk2 1997
     
  10. Zack101

    Gangster

    Joined: Jul 31, 2011

    Posts: 206

    If you have less than battery voltage, you will have a bad connection somewhere increasing the resistance.
     


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