Funny temp gauge no luck with the search

[binger59]

So My alternator went a few weeks ago and no I've got gremlins. Temp gauge goes to the right (pegged) when van is turned off. The oil light slowly comes on when van is sitting not running. When I'm driving the temp gauge comes back to the left to anywhere in between the led and the thin white line. I pulled the coolant level sensor off and no lit led on dash, also the button temp sensor on t-stat disconnected and no response. I also checked the Voltage regulator and went so far as changing it and nothing. I'm not having any problems with the gas gauge, so I'm thinking it's something else. New alt is putting out 13.99-14.00 v. Is there anything else I can try? I'm wondering if I blow a hose or if the vans procedes to get warm Either the fan won't turn on or I won't know of a problem until I see the white cloud. Can the 14 pin connecter for the clock and other stuff be a problem. Any help or suggestions would be very helpful. Thanks everybody.
_________________
Binger

1984 Westy
1986 7 Pass R.I.P. Donor van
2019 Jetta
2014 Passat
2019 Atlas
2006 Passat R.I.P.
1998 Jetta R.I.P.
1984 Vanagon R.I.P.

[Perales]

Is this a "new to you" van? Did it behave itself before the alternator swap? It sounds like there might be some creative wiring going on and it is always helpful to be able to blame the PO! How are you at reading a wiring diagram?
_________________
-- 1987 Westfalia automatic (Captain Vino)

[rolfsky]

The other day I bought a VDO temp gauge from an early Cabriolet and was testing the backlight by applying 12V via a a bench power supply. While checking the light, I kept accidentally pegging the display when I made contact with the sensor input on the gauge. To the best of my understanding, these gauges work by monitoring resistance, lower resistance equals higher reading. By applying 12V with effectively zero resistance, it was reading "very hot".

With the ignition in the "on" position (engine off), try pulling the negative battery cable and seeing if the gauge drops to where it would normally be when the key is removed. Based on the testing you've already done, it's probably current backflow problem... melted wires, crossed wires, improperly reattached to the alternator?
_________________
'85 Merian brown Vanagon Westfalia