Lights/heater issues

Discussion in 'Freightliner Forum' started by Randyjh, Feb 18, 2013.

  1. Randyjh

    Randyjh Bobtail Member

    7
    2
    Feb 18, 2013
    0
    I have a 2004 classic xl. A couple weeks ago, the speedo started to act up. It would work, then stop so I replaced with a brand new one. It seemed to fix the issue for about an hour, then it started again.
    Then last week, my heater does not work, brights do not work.

    I started to look at the issue closely then I started to be chasing issues. One thing will work, then stop then another thing will start working then stop. It seems to be connected to the high beam lights.

    Now as of last night, when I have the truck running-low beams on the tach works, but the speedo and heater fan does not. I also noticed that when I engauge the fan hub the light will come on. When I switch to the high beams--no tach--no speedo--no heater--the light for the fan hub goes out--in fact the only indicators I get when it I have the high beams on is the directionals.

    I am at a lost, it seems like a short but I cannot locate it.

    Any suggestions or possibly a wiring diragram would help me chase the problem. I am at a loss and need to get the truck back on the road as soon as I can.

    Thanks
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Pablo-UA

    Pablo-UA Road Train Member

    7,604
    1,640
    Oct 11, 2010
    Borispol, Ukraine
    0
    check wiring to cab fuse panel. There are two thick (about 16 mm2) wires. Red - power supply and wight negative wire (marked GND). They run from starter area and may be corroded. Usually ground wire is corroded
     
  4. Randyjh

    Randyjh Bobtail Member

    7
    2
    Feb 18, 2013
    0
    I had thought grounds at first, but I did check all of them and do not see any issues. I am going to try to run a new ground to see if that helps.
     
  5. rjones56

    rjones56 Heavy Load Member

    823
    486
    Jul 15, 2008
    staunton va
    0
    To quickly test ground you can use a good pair of jumpercables attached to cab framework and the truck frame.
     
  6. carrkool

    carrkool Heavy Load Member

    883
    494
    May 10, 2012
    adah, pa
    0
    these classics and flds where good for this. check and clean all of your relays and breakers. moisture builds up over time in there and corrods everything up and they start doing this. i spent a week chasing wires and testing to find that it was this issue. the next truck that started to act like this i went start there cleaned and was working again. the pain is you might need to pull every breaker out to get the back of the feed strip cleaned off good.
     
  7. Randyjh

    Randyjh Bobtail Member

    7
    2
    Feb 18, 2013
    0
    I tried the jumper cables to the fame and the breaker panel. I also tried it direct to the battery. i am still having the same issues.
    I am going to dig into the wire harness where it comes into the cab. I have a feeling that there may be a short here.

    I also put a new ground from the motor to the cab. This did not have an effect. I figured since it starts fine and runs fine, the grounds to the starter and motor have to be OK.

    I pull the relays for the headlights out, and now my low air light functions normally.

    I can now get the heater to work, only when the motor is running. I have to start the truck, then turn on the running lights. the heater fan will work until I shut the truck down.

    Any other thoughts.
    Gotta love the salt and chloride. eat the hell out of wire where you cannot see them.
     
  8. Randyjh

    Randyjh Bobtail Member

    7
    2
    Feb 18, 2013
    0
    Found the problem. The circuit breaker that feeds the relays for the heater and lights and numerous other items was bad. It was only letting about 4 volts thru it. I noticed a dim light on my test probe and then took a voltage reading. When I removed it, it ohmed out at about 50 ohms. this should be 0. I replaced it, and everything works perfectly. Two weeks and lot of work for an $8.00 part.

    I would have placed money on a ground issue, but it was on the power side.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.