Dag061583 Posted August 3, 2017 Share Posted August 3, 2017 I'm working on a 2001 mack ch613, the hi beam lights up with the flash to pass but not with the dimmer switch. The dimmer is working like it should at the column but no change in the head lamps. Is there a relay that controls the hi beam on/off and if so where is it located? I've checked the fuse box on pass. Side of dash but nothing is labeled. Any schematic or advice would be much appreciated!!! Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted August 3, 2017 Share Posted August 3, 2017 This is your vintage. Enjoy! Tilt ray is your relay for headlight dim. Go to the tilt ray relay spade 86 & 85 for answers. Test 3-E-0.8 for ground and 3-B 1.0 for power. Manipulate them with switches and then you establish if it is a switch issue. schem1.pdf schem.pdf Quote Link to comment Share on other sites More sharing options...
Dag061583 Posted August 4, 2017 Author Share Posted August 4, 2017 Thank you for the advice and schematic. When testing I found one leg in the tilt Ray circuit to pulse between + and -. Is that normal. The switch seems to be functional. I can jump the relay and the hi beams come on. But not with the switch. I've swapped the relays and still no Good. Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted August 4, 2017 Share Posted August 4, 2017 1 hour ago, Dag061583 said: Thank you for the advice and schematic. When testing I found one leg in the tilt Ray circuit to pulse between + and -. Is that normal. The switch seems to be functional. I can jump the relay and the hi beams come on. But not with the switch. I've swapped the relays and still no Good. Pulse is not normal. It's not logical enough to be switching it's own polarity. You must have a thermal auto-reset fuse opening and closing relative to it's own temp. Follow the circuit backwards to the cause of short. Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted August 4, 2017 Share Posted August 4, 2017 I once had a dash "smoke out" on a truck that was pulsing the thermal reset fuse. The guy had been driving it that way for days (weeks?), eventually the fuse will fail closed and WHOOF. Burned the harness from the turn signal switch to the main power in about five seconds. Glad I was driving around the lot not on the road, rubber insulation smoke is tear gas. Fuse turned a defining color. 1 Quote Link to comment Share on other sites More sharing options...
Tired Posted August 26, 2023 Share Posted August 26, 2023 Did you ever figure out what it was?? I am having the same issue Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 28, 2023 Share Posted August 28, 2023 That post is 6vyears old, I suggest you start a new thread, include year, model, and engine series, and tranny.. Quote Link to comment Share on other sites More sharing options...
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