[Tim]

Sounds like a common ground is loose.

[Archived]

I would give one of PC advertisers a call;

Jeff…. at East Tenn Lux Coach

Brian…at American Fleet

Lewis…….. Expert Allison Transmission

[Dick]

It does sound like a grounding problem. Try to think what goes “on” when the park brake is “off” and start looking there. On my bus the daytime running lights are powered only when the brake is off.

[Tim]

On our coaches the engine needs to be running, the brake has to be released and the transmission has to be in drive.

That’s a lot of places for a faulty current path to happen and I think the starting point has to be asking Prevost to help diagnose it.

[needtocamp]

Interesting new piece of info:

When test driving the bus before purchasing – and checking the engine, trans, etc… out we never noticed this problem. Nor did we on the entire trip home from Pheonix to Livermore.

We drove pretty much straight through to get home in time to take the kids out for Halloween, so we drove all night too. That’s when we, like many of you, figured out the headlights were pretty lame.

Very quickly after that, one of the first things I did was change the headlights from a halogen bulb – to an HID setup for much better light. I’ve done that on quite a few vehicles and that was that.

Then – quite a bit later, we drove the bus around and discovered this problem. During the daytime.

I don’t know why… but the other night, I ran the bus trying to figure out the problem and as I was sitting there I reached out and hit the headlights. Don’t really even know why I did…. and the problem stopped.

I then did some testing and figured out as long as the headlights are on – not just the parking lights but the headllights – the problem doesn’t happen.

Yesterday we took a “learning” trip to Bravo Farms for the kids to play in their playground. A nice 2.5 hour drive each way and I left the headlights on the whole time. No problems.

So – now at least I figured out a way around the problem… now I’ll have to figure out what it is. Obviously, I now think it has to do with the HID modification I did. Which is pretty simple. Take out the old lights and put in a new light. Same plug and everyhting… no “modification” there.

We’re planning to go to Prevost Mira Loma soon – I will discuss it with them in person when the bus is there to see it.

Thanks all! Posting so it’s on the record hopefully to help someone in the future…

[Walter]

I might of missed something when reading this however it sounds like could be tied to the daytime run circuit as this has been a issue when switching to the other lights….

[Walter]

Jeff’s advice sounds correct. When I changed out fro mthe standard headlights, we had to disable the “running headlights”. This was done via the relay io nthe drivers compartment. it is clearly labeled. Removing the relay solved the problem. However, fro mthen on had no running headlights. The headlights only worked with the switch.

[June]

That sure sounds like a possibility. I will check that out. Thanks!

Walt

[Archived]

I simply took out the relay looking thing that said Daytime running lights and it has gone! It was definitely a strange problem.

I don’t know exactly what was happening – I’d sort of like to understand it. And, having daytime running lamps would be nice. I might just try some other type of setup, like and led strip or something

Thanks for all the help everyone!

[Joe]

Day time run headlights are a reduced voltage and the HID headlights do not function properly at that voltage…

[Brady]

If you get a chance give Marathon a call as there is a wire change to bring back daytime run lights.

Another vendor is EX-caliber in Sanford, FL. who does build the headlight change / upgrade and includes wire change. Don’t know if he sells the wire kit seperatly.

Usually the vendor selling the less costly headlight upgrade includes a note to pull the day time run light {DTRL} relay.

FWIW….

Did the headlight upgrade on both Prevost”s I’ve owned getting the kits from EX-Calibur keeping the DTRL feature.

Without the wiring change you can have daytime run lights, simply by turning on your headlights switch. Of course all your other exterior bus lights are on.

[Archived]

OR, the other alternative is to make a wiring alteration of the control wire to the high beams instead of the low beams, as Prevost does on all the new shells. This causes the high beam bulbs, which are halogen – not HID, at partial intensity. Doug’s wiring kit just makes the HID bulbs come on full bright, which is fine I suppose, but also uses up their life during daytime driving, and can confuse you when it gets to dusk because they are on at full intensity while the marker lights are off.

[John]

This sounds like the winner to me. I’m going to work on that one. Thanks!

Walt