Turning lights, horn, fuel gauge cacked out all at once!

[dpd]

Hi all,
Took the Delica camper out to a festival this weekend, and after getting on the road noticed a few things suddenly broken!

Left and right turn signals are unresponsive, horn does nothing, and fuel gauge is unpowered.

I have checked the turn signal fuse in the fusebox, and yes it is burned up. Replacing it and turning the key to on just burns another fuse. I'll trace this the best I can to try to figure out the cause, I have done lots of work on the electrical lately including dual starter batts, dual rear batts, inverter, onboard charger, trailer harness. So I probably broke it in the process, though I can't think of how I would have.

There are a few things confusing me though:
- why are the horn and fuel gauge gone, along with the turn signal fuse?
- why do the hazards still work, when the turn signals don't? Does that rule out a short in the light bulb fixtures?
- Do the hazard lights have their own flasher relay, or do they just activate the turn signal relays in unison? Can I rule out broken turn flasher relays because the hazards still work? (this might narrow it down to 'before the relays' at least)
- Where are the turning signal flasher relays anyway?

Thanks for the help as always,
David

[Green1]

- why are the horn and fuel gauge gone, along with the turn signal fuse?

they're on the same fuse.

- why do the hazards still work, when the turn signals don't? Does that rule out a short in the light bulb fixtures?

They're not on the same fuse. and yes, it indicates that the turn signal fixtures are not the issue.

- Do the hazard lights have their own flasher relay, or do they just activate the turn signal relays in unison? Can I rule out broken turn flasher relays because the hazards still work? (this might narrow it down to 'before the relays' at least)

I don't know...

- Where are the turning signal flasher relays anyway?

behind the glove box

if simply turning the key to on burns the fuse without activating anything else, you are dealing with a short before the switch, or in an unswitched circuit.
I'm not entirely sure what all is on that fuse, however I'd be inclined to start by checking the connections inside the steering column (that will help rule out the wiring to both the signal light switch as well as the horn) this still leaves the fuel gauge circuitry, and possibly others...

[dpd]

Thanks for the tips Green1.

When you say 'because they are on the same fuse', are you deducting that from my problem, or do you know it for a fact? I'm just trying to figure out if it's one problem I'm dealing with, or a few co-existent ones. I notice on the L300 fusebox layout that there is a separate horn fuse, I'll check that one when I get home today, although there are a few differences in the fusebox between a passenger model and my work-van based camper that have complicated things for me before.

I think I'll start in the steering column as you suggest, and I'll test to see if the turning signal wire in the harness is grounded, or gets 12v coming out of the steering column, and rule out a short in there. By any chance do you know which wire in the harness activates turn signals? I can probably figure it out with the harness disconnected unless the problem is in the column itself...

Thanks again
David

[dpd]

Oh, and does anyone know how the turn signals work electrically, between steering column and flasher relays?
If both sides' on-signal pass through a single 15A fuse, how do the relays tell which side is being signaled?

[Green1]

When you say 'because they are on the same fuse', are you deducting that from my problem, or do you know it for a fact?

because when my horn blew a fuse I lost those too...