After purchasing my MH in the USA, and bringing it into Canada, part of the required changes for importing the unit into Canada is the addition of Daytime running lights. DRL. Because the Freightliner Chassis was prewired for DRL, I ordered the F/L control module, and installed it. Passed all the inspections and headed south for the winter. 5 hrs on the road later , I-5 south of Seattle in the dark, the head light switch circuit breaker starts tripping. Pulled off and mis-takenly blaming the DRL, disconnected the module. 10 min. later head lights flashing again; got to a rest area and stopped for the night.
Played with the relays for the headlamps, and found that with the left headlamp relay removed I had low beam on both headlights and the circuirt breaker didn't blow. Ran the rest of the winter with low beams only still blaming F/L for this problem.
Got home , joined iRV2, & Access Freightliner. Pulled up all the wiring diagrams I could lay my hands on, and tested ;with a replacement relay F/L wiring. All OK. Then I found the real problem.
A non-F/L front end harness splices both low beam wires together and both high beam wires, the wiring goes into an 8 space multiple connector; with 2 empty spaces; then splits the wires back to left and right 1 foot after the connector.
What happened was one relay stuck, holding both high beams on. The second relay when switched to low beams turned them on at the same time. 4 light filiments drawing power, over loads the head light switch, and the circuit breaker trips. 2 filiment load design.
So what have I got , besides a headache.
Instead of one headlight stuck on high and the other switching. I've got 2 overheated headlights, both filiments on they don't cool enough to survive. An overworked headlight switch, from multiple tripping of the circuit breaker, the right headlamp relay overheated from running at double design load. All because the designer of the front end harness decided to save 3 feet of wire!