balfarmsmack316 Posted March 28, 2008 Share Posted March 28, 2008 Have a 2002 CH 613 and cant get the outside roof marker lights to work and have no power to the trailor marker light wire. Have ck fuse and changed both headlight and marker light switches and the relay in the curcit panel under hood. Anyone have any ideas. Could it be in the turn signal? Quote Link to comment https://www.bigmacktrucks.com/topic/3563-cab-roof-and-trailor-marker-lights/ Share on other sites More sharing options...
ciw65 Posted March 30, 2008 Share Posted March 30, 2008 I love these tricky ones. NOT. Problem is never where you think it will be. Is the truck fitted with a circuit protection box for the trailer wiring. They can be a source of many problems. Is the marker light fuse shared with any other circuit, as this can create problems on a completely different circuit. If it was just the cab roof lights I would say check your cab earth first, but trailer not working as well tends to point at the one power circuit. You have a seperate switch for marker lights, or do they come on with headlight switch in "Park" position. If they come on with headlight switch, I have found sometimes the contacts in the headlight switch can be a problem. I guess best thing is to break out the test light and see if you have power to the switches and relays. Also ensure you have a good earth for the relays and that they are working. Wouldn't be the first time a "new" switch or relay didn't work. Quote Link to comment https://www.bigmacktrucks.com/topic/3563-cab-roof-and-trailor-marker-lights/#findComment-17936 Share on other sites More sharing options...
ciw65 Posted March 30, 2008 Share Posted March 30, 2008 If you can point me at an online wiring diagram I might be able to sus out a potential problem. Quote Link to comment https://www.bigmacktrucks.com/topic/3563-cab-roof-and-trailor-marker-lights/#findComment-17937 Share on other sites More sharing options...
madscout Posted April 1, 2008 Share Posted April 1, 2008 Worked on a Vol@$# once that had a problem with the marker interupt switch (flash the light switch) that was causing close to the same problem. Just a thought. Quote Link to comment https://www.bigmacktrucks.com/topic/3563-cab-roof-and-trailor-marker-lights/#findComment-18006 Share on other sites More sharing options...
davekt Posted April 23, 2009 Share Posted April 23, 2009 Check the roof harness connector located at the left A Post area, sometimes the windshield will leak and cause the terminals to corrode. Quote Link to comment https://www.bigmacktrucks.com/topic/3563-cab-roof-and-trailor-marker-lights/#findComment-34284 Share on other sites More sharing options...
mackmech Posted June 8, 2009 Share Posted June 8, 2009 the relay for those lights get a ground through the turn signal like switch like as you thought check terminals in relay box under hood they very prone to corrosion in my experience it is either relay box or turn signal switch Quote Link to comment https://www.bigmacktrucks.com/topic/3563-cab-roof-and-trailor-marker-lights/#findComment-36306 Share on other sites More sharing options...
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