Low beams headlights not working

[Mortdd]

What happens when your RV place can't find the issue after hours of looking? High beams work, low beams do not. The high/low beam switch has been checked, the lights have been checked by a direct connect and they work etc.

[tropical36]

I'm going to assume that proper trouble shooting procedures were done and without guessing at things. Having said that and what stumps some techs. is that sometimes you'll see voltage present, but don't realize that it disappears, once under load, like with trying to turn the lights on. This can be due to a poor ground connection or with relay contacts that are feeding the circuit, just for two examples and you did say that directly wiring to the lights worked.

[enblethen]

Sounds like it may have been the "Central Junction Box". That is where the relays should be.
Thanks for the update!

[donfrump]

Mortdd wrote:
Update, the problem was finally found, the RV repair shop had to bring in someone to help and it turned out to be a wire that come out of some box. They could not really explane much more without my coming onsite so they could show me but they took pictures so I can see them when I get a chance to pick it up. Thanks for all the responses, they were good just not the correct thing.

sounds very plausible as I could not see two fuses blowing at once etc
thanks for the update

[AllegroD]

WyoTraveler wrote:
Probably a bad connection. I would unplug and plug in all connectors and see if that helps.

X2 We had this happen mid trip on our previous F53, 2004 Coachmen Aurora, 3480DS. It turned out to be wiring at the column.

[Mortdd]

Update, the problem was finally found, the RV repair shop had to bring in someone to help and it turned out to be a wire that come out of some box. They could not really explane much more without my coming onsite so they could show me but they took pictures so I can see them when I get a chance to pick it up. Thanks for all the responses, they were good just not the correct thing.

[tderonne]

slickest1 wrote:
There is a module that controls that and it was bad.

No such module on an F53. See the wiring diagram already posted.

[slickest1]

I just went through the same thing with my Chevy Trailblazer. No low beams and no daytime running lights. There is a module that controls that and it was bad. The high beams worked and the fuses for the low beams were good also.
I suspect that your problem will be the same.

[Jim]

Check for broken or corroded through terminals at the relays under the hood.

It sounds like this shop has no clue how to do electrical testing, I'd move on, quickly.

[donfrump]

enblethen wrote:
tderonne:
That is almost the same drawing I was looking at.
Main difference it show on the drawing I was looking at F1-10 feeds the low beams and DRL.
Jumper from F1-27 only feeds the high beams plus passing light
K53 is for DRL and low beam switching.
Still looks like blown fuse F1-10.

as shown/posted a couple times there are *TWO* 10 amp fuses one for left low beam and one for right low beam
chances of the OP having two blown 10 amps fuses are pretty remote

I think headlite relay or switch as most likely or misdiagnosed H/L switch

[tderonne]

But 1-10 only supplies power to the DRLs. Low/high beam comes from 1-27.

[enblethen]

tderonne:
That is almost the same drawing I was looking at.
Main difference it show on the drawing I was looking at F1-10 feeds the low beams and DRL.
Jumper from F1-27 only feeds the high beams plus passing light
K53 is for DRL and low beam switching.
Still looks like blown fuse F1-10.

[tderonne]

Ford F53's use the low beams for the DRLs.

Here's an overview of the F53 headlight wiring:

The three wires at the lower right go to the left and right low beams and the high beams.
(From the 2002 manual, but all V10's are the same as far as I've seen.)

[enblethen]

I did not find a wiring diagram for the F53. I did find a wiring diagram for E450.
The low beams are fuse at 20 amp fuse 10.
Then go into the multi-function switch.
Low beams then go to a Central Junction box where they are again fuse, but a 10 amp. Fuse 25 and fuse 31
Since both are out, check owners manual for low beam headlight fuse.
Then check the connector on the multi-function switch on steering column.

[DrewE]

tderonne wrote:
Daytime Running Lights don't work either I assume? If that's the case, it pretty much has to be the low beam fuses. Odd, but not impossible.

Most DRL systems that use the headlight bulbs at reduced power (rather than having dedicated lamps) use the high beams. You don't really want the low-beam cutoff for DRLs, as that somewhat works contrary to their intended purpose of making the vehicle more visible.

I don't know how the Ford chassis specifically does this, nor whether it may somehow route the DRL current through the low-beam fuses. Goodness knows that vehicle manufacturers sometimes do rather counter-intuitive things when designing the wiring.