Volkswagen Passat (2001 - 2005) - 01 1.9TDI brake & fog light fuse | Technical matters | Back Room Forum

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Sun 17 Aug 2008 15:24

01 1.9TDI brake & fog light fuse - hewshotter

2001 Passat estate 130TDI

I've just managed to blow a fuse (or two) while repairing/checking a trailer light board. I found and successfully replaced the 5A tail light fuse in panel at RH edge of dashboard but cannot find a fuse for the rear fog lights and brake lights. They are not listed on the card in the fuse panel. Does anyone know if there is a second fusebox and if so where is it? I read another post about the brake light circuit being linked to the engine management circuit - is this a clue?

Thanks

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Sun 17 Aug 2008 15:47

01 1.9TDI brake & fog light fuse - Screwloose

The rear fogs could be on fuse 36, or fuse 10 and the brake lights on fuse 13, fuse 20, or fuse 7. Or not; as they move about a lot over the years, depending on equipment levels and '01 is a change year too.

It will be one of the dash-end fuses though; there are four other boxes, but mostly for other functions.

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Sun 17 Aug 2008 16:19

01 1.9TDI brake & fog light fuse - hewshotter

Thanks - I will look again but I think I have already checked every fuse in that panel! If not where is the box that deals with the engine management because another post was talking about the brake lights being linked to the EMU in order to prevent you brake and accelerating at the same time. Must be too many would-be rally drivers out there in Passats...

Cheers

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Sun 17 Aug 2008 16:50

01 1.9TDI brake & fog light fuse - Screwloose

Are you getting any bulb-failure warnings? On that year, you're right on the start of the deeply-weird electronic pulse-driven rear lighting. [Pray you haven't fried that!]

The EMU does have a separate circuit in the, twin-track, brake-pedal position sensor and does monitor the brake light circuit too as a check on it. It's function is to cut the engine to idle as a safety back-up in case the fly-by-wire electronic throttle throws a wobbly. The EMU fuses are in the fusebox in the heater plenum chamber, driver's side.

Just how bad a short did this trailer-board cause? Surely the socket must have a smart-box on a car with ECU-controlled lighting and should have it's own feed and fuses? Who fitted it?

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Sun 17 Aug 2008 17:03

01 1.9TDI brake & fog light fuse - hewshotter

Hmm It's getting interesting now. Just by swapping fuses around I've got the fogs working but no brake lights yet. Went for a test drive and got a stop message/engine coolant warning which could be the rad fan fuse, but on a second test drive no problem and it now seems fine.

The towbar pre-dates me but is not factory fitted.

The short was my fault - I was trying to apply the brakes and simultaneously use a multi meter to test for voltage on the unplugged brake light leads on the trailer board. Managed to touch two live wires.

I don't think it's the latest version - it is just a pre facelift model so hopefully the rear lights are not the latest spec. Each rear cluster has four double filament brake/tail light bulbs. There are no bulb-failure lights on the dash. The trailer board has been connected in to the rear light wiring harness so no smart box.

Anyway thanks for all the advice - looks like I'll be off to the local auto electrician tomorrow. Doh!

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Sun 17 Aug 2008 17:21

01 1.9TDI brake & fog light fuse - Screwloose

Multimeters are a pain for jobs like that; I always use a good old test light.

To check fuses; turn the ignition on and every fuse that is live at one end should also be live at the other.

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Sun 17 Aug 2008 17:38

01 1.9TDI brake & fog light fuse - hewshotter

Well I think my eyesight must be on the way out. I just checked all the fuses again and one that looked good had in fact blown. So could have saved myself hours. Anyway all lights on car and trailer board now working. Hurrah!

Thanks again.

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