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Discussion Starter · #1 ·
Recently purchased a 99 Passat sedan 1.8T 5sp and while i was cleaning the inside today I knocked off my fuse panel cover and discovered a jumper wire (looks like a small piece of speaker wire) going between fuses 37 and 34 ... in my owners manual it says fuse 37 is radio and fuse 34 is engine timing. Does anyone know why this would be there? I will include a pic to show it ...
 

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Because someone was lazy, or cheap... And to drain your battery a bit.

Fuse 37 is the radio, and is hot at all times.
Fuse 34 powers many valves and sensors in the engine, but the fuse is downstream of the fuel pump relay, i.e. it should only be hot when the fuel pump relay is energized. The fuel pump relay is controlled by the ECM, and is, of course, off when the engine is off (except for priming).

That wire shouldn't be there, but the car might not run without it. If you're really lucky, it's just a leftover troubleshooting wire.

Ref: Bentley schematics 37 and 30.
 

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Discussion Starter · #3 ·
Thanks ... if I disconnect it and the car won't run does that mean I have a major problem to solve?
 

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Discussion Starter · #5 ·
Well I went out to check it at lunch and see what would happen ... when I unplug the radio fuse the car will crank but will not start. Plug the radio fuse back in and it starts right up each time.
 

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This is really strange to me. I'm curious as what would happen if you remove both of the fuses and replace them with two new 20A fuses.
 

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Have you replaced both fuses? Fuses sometimes look OK, but don't actually pass current. Before troubleshooting further, I'd replace both and see if the car runs w/o the jumper.
 

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Discussion Starter · #8 ·
Ok ... I will try that and see what happens. Will keep you posted on it ... thanks for the help.
 

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Discussion Starter · #9 ·
Update ... pulled both fuses and replaced them with new ones ... radio plays but car won't start ... pulled radio fuse and put it in slot 34 just to make sure fuse is good and then put another fuse in radio slot ... still no start, cranks but no start and when key is released I can hear a tick from fuse area that sounds like maybe a relay ... put both fuses back in with a fuse tap on each one and a new jumper wire with two slide connects on each end ... yep, it starts right up every time.
 

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I like to see both fuse and relay for fuel pump are checked and verified.
 

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Discussion Starter · #12 ·
Sorry so late with an update, been out of town ... drove to the parts store to get a Haynes manual so I could find the fuel pump relay to try and test it and on the way my battery light came on and then would go off when I was above about 2k rpm but every time the wipers came on battery light would come on again and then go off. So I had the guy at Auto Zone check the battery and alternator and battery is ok but alternator is not charging except when rev the engine up and the light goes out so looks like now I am gonna need an alternator. Spoke to my mechanic and he says he can do my TB, WP, thermostat kit from Blauparts and the alternator all at the same time for 150 to 200 which sounded like a good deal on the labor so I am just gonna put it in the shop for a few days to get some maintenance work done. While its there I'll get him to check out that relay too.
 

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Apparently the preferred solution for an ailing alternator is to have the factory alternator rebuilt, not replaced with a remanufactured unit. Of course you would have to ensure the one currently installed is a factory version. Otherwise you would have to source one from a salvage yard.
 

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You almost certainly have a faulty FP Relay, the only other possibility is a fault in the wire between the FP Relay and fuse #34.
 

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Discussion Starter · #16 ·
Apparently the preferred solution for an ailing alternator is to have the factory alternator rebuilt, not replaced with a remanufactured unit. Of course you would have to ensure the one currently installed is a factory version. Otherwise you would have to source one from a salvage yard.
I have seen that on several posts on here about rebuilding factory unit, I will check with my guy and see if he could do it and try to find a rebuild kit. As far as I know it is the original alternator, but will know for sure when it comes out I guess.
 

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Sorry for the side note, but I have an on-going thread related to no start - no crank situation and it was suggested to ensure all the right fuses are in place. My question is by looking at your picture of the fuse panel with jumper wire, the fuse values seem to be similar to mine. But according to the fuse layout and the required fuse value, I see a lot of yours (same as mine) where there is a higher value fuse (i.e. - Fuse #28 calls out 15 amp, yet a 20 amp fuse is installed). Is this typical as I have about 12 fuses with higher than required amps? I have 2000 1.8T, 5-speed. Thanks.
 
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