Number 9 fuse keeps blowing

[Mike C]

1970 bus all stock

This morning driving to work the gas gauge suddenly dropped to empty. Then turn signals stopped working. I got to work and saw that the gen and oil light were not turning on when I turned the key. I figured it was a fuse and that it would be an easy fix. I replaced the fuse and it blew. Checked out the connections--looked fine and the fuse blew again. I searched and found a few ideas on how to make a fuse testing light so that I don't keep blowing fuses. I can work on that tomorrow.

Where would I start trouble shooting? This is the first time the bus has had fuse issues. It starts and runs fine, but don't like the idea of driving without the oil and gen light working. Just as I was about to try to trouble shoot it began to rain...go figure. I appreciate any feedback. Thanks.
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Bone stock 1970 non-walkthrough "Station Wagon" bus

[quote="1977_L63H_P27"]As mentioned before, it's a 9-passenger Deluxe. The true "station wagon" of buses.

[busdaddy]

You'll have to find what's touching a grounded surface, the back of the fuel gauge is a common one as well as multiple parts of the signals starting with the hazard switch.
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[Mike C]

Thanks Busdaddy. I appreciate the help.
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Bone stock 1970 non-walkthrough "Station Wagon" bus

[quote="1977_L63H_P27"]As mentioned before, it's a 9-passenger Deluxe. The true "station wagon" of buses.

[telford dorr]

Be sure to check the hazard switch itself to see if it has popped apart and shorted against something.

Be sure to disconnect the battery before messing with the switch - it's 'hot' (terminal 30) all of the time...
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'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[Wildthings]

This diagram is for a later bus. But if you look at current tracks 39-50 you will see everything that is fed by the S11 fuse (equivalent to the one you are blowing).


Double click to enlarge

[Tcash]

http://www.thesamba.com/vw/archives/info/wiringt2.php

http://www.thesamba.com/vw/archives/info/wiring/70busfuses.jpg

http://www.thesamba.com/vw/archives/info/wiring/baybus_70a.jpg

[Mike C]

So, I can't find anything out of the ordinary--grounding, etc. The hazard switch is working fine and isn't related to the #9 fuse (at least on my bus). I've traced the wires behind the panel and nothing. The one thing I did realize since I'm having fuse issues is the PO replaced the fuse box to fit 7.5 fuses instead of 8:

The problem #9 fuse slot:

So, the only thing I haven't done is take all of the wires out and make a mess of them (electrical is beyond me).

The bus is running just great and have held off driving it to work (I'm a Homebound special ed. teacher which takes me all around the Albuquerque area) since the oil and gen light are not working.
Would you still drive it even though those lights weren't working? What should my next step be besides taking it to the local VW shop?
I was even thinking of replacing the fuse box to a stock VW one, but all electrical have been working fine until this blasted #9 fuse.
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Bone stock 1970 non-walkthrough "Station Wagon" bus

[quote="1977_L63H_P27"]As mentioned before, it's a 9-passenger Deluxe. The true "station wagon" of buses.

[telford dorr]

From the Gallery:

Cobb together one of these. Use it to jump the fuse that keeps blowing. It will light up. Start disconnecting stuff and moving stuff until the lamp goes out. Whatever made it go out is the problem.

Note: 7.5 is close enough to 8. No fuse runs near max ratings, so it should be OK.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[Mike C]

[Tom Powell]

[Tcash]

Wouldn't this accomplish the same tests and fit into the tool box easier?
It can also be used to test power to the running lights by laying it on the ground and viewing in the mirror or through the windshield.

Aloha
tp[/quote]

Compared to a 8 amp fuse the filament is much smaller. The filament in the bulb would overheat and melt-blow, when the current in the circuit became too high.

[telford dorr]

[Tcash]

A Circuit breaker of the correct amperage wired in place of the fuse works well too.

[telford dorr]

In this case, it's not very convenient. Until the short is cleared, the breaker will open instantly, giving little time to troubleshoot. The lamp will just light up, dumping limited current into the short. This allows troubleshooting (the lamp will go dim/dark when the problem is found).
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[Tom Powell]

[Mike C]