It is useful to have made electronic ITIS ...
I unfortunately stumbled apparently in the only spare part available for the VW T4. The offending part is the fresh water level gauge, which is that thing that should send the ECU to control the water level in the tank to show the display control the water level in real time.
The probe in question was produced by Barksdale, marked UNS2300-ABS is a technically subject to the VW list price of € 125, but reportedly Autogerma, is not longer available (though the medium is 2000).
I unfortunately stumbled apparently in the only spare part available for the VW T4. The offending part is the fresh water level gauge, which is that thing that should send the ECU to control the water level in the tank to show the display control the water level in real time.
The probe in question was produced by Barksdale, marked UNS2300-ABS is a technically subject to the VW list price of € 125, but reportedly Autogerma, is not longer available (though the medium is 2000).
probe VW T4 level G33 (G33 Wasserstand Frischwasser Geber)
The piece looks like a simple plastic tube with a cable with two poles. Inside hides it seems the reed-switch to mercury-sensitive magnetic float, that with time they break or do not respond correctly.
There are several post on this sensor network, the best known is this .
After unsuccessfully sought an alternative, including ebay and various specialty retailers, with the help of ufo rispoli (www.quantotira.net) I mounted a small electronic circuit that simulates the operation of the original probe , but using a simple plastic rod with 4 screws, welded respectively 4-wire connected to the control circuit.
The new sensor uses conductivity of the water, depending on the level, go to pilot the various ports of built-CD4066, which inside contains 4 mini-switch solid state. Through
Miniswitch is going to generate combinations of strength required by the unit, namely:
- full, 3 notches: Short circuit
- 2 bars: 720 ohms
- 1 notch:
1k6 ohm - blank: 6K2 ohm
These combinations are obtained by paralleling resistors 3, respectively 6170, 2190 and 1292 ohms, the exact values \u200b\u200bobtained by adjusting the trimmer 10k, 5k and 2k.
The circuit is very simple, in theory, consumes so little that you can always leave it connected. However, I have planned to install a switch to turn it off when the tank is empty in winter, in order to avoid unnecessary loads.
cap should be clearly recovered the original probe, sawing the auction, clearing the hole, adjusting to the new auction. To seal the hole, I used the normal hot glue.
new probe and circuit
There are several post on this sensor network, the best known is this .
After unsuccessfully sought an alternative, including ebay and various specialty retailers, with the help of ufo rispoli (www.quantotira.net) I mounted a small electronic circuit that simulates the operation of the original probe , but using a simple plastic rod with 4 screws, welded respectively 4-wire connected to the control circuit.
The new sensor uses conductivity of the water, depending on the level, go to pilot the various ports of built-CD4066, which inside contains 4 mini-switch solid state. Through
Miniswitch is going to generate combinations of strength required by the unit, namely:
- full, 3 notches: Short circuit
- 2 bars: 720 ohms
- 1 notch:
1k6 ohm - blank: 6K2 ohm
These combinations are obtained by paralleling resistors 3, respectively 6170, 2190 and 1292 ohms, the exact values \u200b\u200bobtained by adjusting the trimmer 10k, 5k and 2k.
The circuit is very simple, in theory, consumes so little that you can always leave it connected. However, I have planned to install a switch to turn it off when the tank is empty in winter, in order to avoid unnecessary loads.
new probe and circuit
final installation
control circuit
display original T4, finally working
detail of the probe craft
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