[xrad]

Anyone have there fuel guage read full all the time. I replaced the tank sensor but no change.



Traced wiring to dash but seem OK. Have not pulled guage to check yet.. I feel it's a short somewhere but where?



any ideas...??

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[xrad]

Traced the green wire fron tank level sensor to gauge cluster and OK

Traced the grey/wt wire(12v power) from tank to gauge cluster and OK

Brown wire at tank sensor grounded OK



Pulled gauges and checked back. Found a melted trace on back of cluster which was right near fuel gauge and connected to green fuel tank level sensor wire (see pic)



So I soldered a jumper and reconnected. Turned on power and everything looked good for 2 seconds, then all gauges dead. Gauge fuse blown. Replaced and it blew again. Obviously a short somewhere.



Now no power to gauges and no power to 12v gr/wt wire at fuel level sensor. Bought another cluster for a 951 and will rerun both 12v and level sensor wire to fuel tank and see what happens...



can't tell if short is in gauge or somewhere else..PO tapped a few lines for stereo...otherwise nothing else abnormal

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[SILVY968]

put an ohm meter across the +12 and ground on the cluster to check for a short. Suspect everything. Do not put back in until you do not have a short on all of the +12 inputs on the cluster. The melted trace was the result of the short, the wire you fixed it with is stronger than the fuse so the fuse will now blow. Pull the gauge and see if you get a short, check the lamps as well.

Good luck

Brian

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[xrad]

Thanks..pulling the gauge right now..

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[RPM]

My gauge never reads full <img src="/forum/images/smilies/968/mellow.gif" class="smilie" alt="" />



Just filled the tank (a quick $58) and even sitting still on level ground it reads about half way into the top section. This seems to be a 944 series quirk. My S2 did the same.



The reserve in the tank is huge. I was below red when I filled up and it only took 16.7 gal.

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[unknown4u]

The guage works fine, If the light will go on then there is a gallon left..................ouch!.

And that is not much when cruising at the autobahn.

I like more reserve.

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[PorscheDude]

IIRC The light comes on when there is 2.5 gals left in the tank.

Mine never reads 100% full.

This is the same on my 951 and my old 944.

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[xrad]

Well, I know the needle can reach above the 4/4 mark so must be the guage needs pot adjustment to compensate for sender signal... More important that it read empty, however.



Checked the circuit plastic sheet, no shorts...could be outside the cluster...eeeesh

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[xrad]

YAHOOO!! found the short!!!



For anyone else with the same problem, here goes:



Bought an 89 gauge cluster, automatic no less. All right, I know...won't work. Well, your sort of right. Obviously, tach is different because of the lever position (N,P,D etc) and the speedo is different (160, not 180) and the fuel/temp gauge see through light panel little different, and tiptronic bulb...etc.etc....



BUT, the flexible rear board is nearl;y identical except for one or two bulb contacts. Board is 95 % same.



So, exchanged my speedo and tach and fuel/temp, inner circuit boards, left all bulbs out, and used the new old replacement bat meter. Of course everything fits. Housings are identical.



Poped it in the dash and hooked up three connectors. Bang, blew instrument fuse. Pulled each connector in turn until I found the one blowing fuses (went through 15 7.5's) Anyway, i ended up isolating (due to location of burned board and from wiring schematics) the region in question. Turns out that 12 volt to gauge bulbs ALSO runs to two inner circuit boards (see pics). I figured that the harness was probably OK except where PO cut in to it (these regions were isolated)



So I repalced the two inner circuit borads with the 1989 boards (same ic's and resistors and caps - just in slightly different arrangement. WELL there she goes...all gauges working ..every one of them..JUST NO LIGHTS NOW...sheesh..



Turns out that in my search for gauge cluster power fuses, i pulled every other 7.5 including gauge light (same as plate light fuse)



Replaced this one and all is well....even have 3/4 tank of gas!!!!



Just have to clean everything and replace....what a PITA.



So, if you guys have a badfuel gauge or temp gauge or problem with bulbs...check the two inner circuit borads (easy to remove and replace..they just seem like a special power supply circuit for different lights and some gauges)

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[Gotter]

A little late on this topic, but for what it's worth, my old 944 would read 4/4 (and even a little past when I'd pull away from the pump.

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[xrad]

Well, everything back together and working very well. Note, while loosening the relays, ended up with winking one up one down headlights. Turned out to be corrosion at relay plugs even though the relay looked all the way in place. Cleaned and works fine now.

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[xrad]

just under 3/4...



checked fuel gauge with spare sender. It can now read just over 4/4 to red light empty.... <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[SILVY968]

xrad,



As you have the spare instrument cluster, can you please get the number from the small black based lamp that is behind the green, PARKING LIGHTS display?

I have one out and the lamps that I ordered have a different mounting base that will not fit properly. The lamp base only says OSRAM 12/1.2, but that does not give me a part #, only voltage and current.

I would appreciate it. If there is no part #, a picture from the side showing the metal fingers would be cool. I can email it to Jeff at Sunset.

Brian

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[xrad]

no real part number..just says



'philips 12/1.2'

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[SILVY968]

thanks.

Brian

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[xrad]

I have a few spares available if you can't find one. Also, you can gently press out the old bulb metal retainer and solder in a new bulb...

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[SILVY968]

I'll give it a try.

Thanks

Brian

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[ExAudiSi]

A little late I know, but if these bulbs are the same as the ones used to light the outside temperature gauge then I believe that they may be the same as the ones used to light the instruments on MkII VW Golfs. Your local VW dealer/independent specialist may be able to assist you.

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