Driving Lights-Finally!

[two2go]

I have posted several questions on this forum about the daytime running lights (DRL) for National RVs and Workhorse chassis. We bought a used coach and the DRLs did not work. I asked my service dealer and the tech. said I do not have DRLs. That despite the Dolphin brochure saying they were standard, having actual lights and working bulbs and a fuse and a relay module.

I started trouble shooting the wiring with the assistance of info provided on the Workhorse forum Driving Lights. I removed the module which is a basic relay and proved that the relay worked, there was a source of 12v, and if I linked the 12v source of the relay socket to the DRL socket contact, the lights lit. Something was not activating the relay so the lights would come on. There was a suggestion that the parking brake had a switch that could be the problem. I tested that switch and it was OK. Also, it seems that the brake switch is connected to the leveling jacks and is instrumental in allowing the jacks to operate only when the parking brake is set. This switch was closing to ground, but I could not test that it connected directly to the DRL relay.

On the relay socket, I was measuring +12v at the 85 and 86 contacts at all times when the ignition switch was on, parking brake on or off, transmission in neutral or drive. One of these terminals has to go to ground to close the relay to activate the circuit to the DRLs, and that was never happening. I looked at the lights while I had my wife at the controls, and I did see a brief flash when she released the parking brake. With +12v at 85 and 86 always, the relay never closed otherwise.

I finally determined that the 85 terminal was steady switched +12v. I don't know where the 12 volts for socket terminal 86 comes from, so I decided it didn't matter and I cut the wire to the terminal underneath the module socket. It is the pea green wire with black trace shown in the photo (orange arrow). The terminal contact is under the near right side of the relay as shown by the pink arrow. I soldered a piece of wire to the green wire and connected the other end to a convenient ground terminal under the dash.



I don't know where the green wire goes or what was feeding it, but I doubt that cutting it off matters. The main thing is that when I turn on the ignition switch, the DRLs come on now. Maybe somebody with a detailed Workhorse wiring schematic can tell me if I messed up.

Here are all six front lights plus two parking lights blazing in their glory. I had previously installed a relay that lights the low beams when the high beams are switched on. The high beams only were not sufficient for night driving.

[Jeepster47]

tow2go,

Are you sure that the parking brake release switch for the DRLs is adjusted correctly. Has it moved slightly due to a loose fastening? If not adjusted up enough it won't allow switch to activate. Just a possibility.

Ed
WCMC - VP West Rallies

[two2go]

Quote:

Originally Posted by Jeepster47 tow2go, Are you sure that the parking brake release switch for the DRLs is adjusted correctly. Has it moved slightly due to a loose fastening? If not adjusted up enough it won't allow switch to activate. Just a possibility.

OK as far as I can determine. Otherwise, the leveling jacks wouldn't nag me to set the brake if I forget and work fine when set. I only saw one switch under there with two wires leading away from it.