Fuel And Coolant Gauge - Inoperative or Malfunction
Group: 90Number: 93-09
Date: June 30, 1993
Subject:
Fuel gauge and engine coolant temperature gauge malfunction
Model(s):
Passat/Corrado
From 1991 m.y.
This Technical Bulletin supersedes Technical Bulletin No. 90-93-05, dated May 31, 1993
Condition
Fuel gauge and engine coolant temperature gauge are inoperative or work intermittently.
Production
Improved VDO circuit boards installed as of 2/92, VIN 31N E 242 000
Service
Check to see if the voltage stabilizer terminals on the instrument panel circuit board are desoldered. If so, resolder the six connections to the circuit board.
Do not replace circuit board.
Note
This procedure applies to vehicles with VDO circuit boards only. VDO circuit boards can be identified by voltage stabilizer in upper right hand corner and VDO identification on speedometer.
Tools Needed
15 Watt soldering iron or pencil
Rosin core or multi-core electrical solder
Damp sponge
^ Desoldering wick
CAUTION
Do not use a soldering gun. These generally have a higher wattage output and can cause damage to circuit board.
Work Procedure
^ Remove instrument cluster from car
^ Remove Instrument panel circuit board from instrument cluster assembly.
^ Inspect six soldered joints on circuit board (arrow)
^ If loose, resolder all six connections.
CAUTION
Use care not to solder across adjacent terminals of voltage stabilizer on circuit board.
Soldering Tips
- Use only a 15 Watt soldering iron with a nickel plated pencil tip.
- Use thin rosin-core or multi-core solder. DO NOT use acid core solder as this is corrosive.
- Use a desoldering wick to remove old solder from the connections to the voltage stabilizer by spreading the webbing over the three connections. Place the soldering iron tip over the webbing and the braid will absorb the old solder as it melts.
- Be careful not to overheat the circuit board.
- Heat the terminal of the voltage stabilizer and the circuit board evenly by placing the soldering iron, tip on the portion of the connection that will absorb the most heat.
- Apply the new solder to the connections, not to the tip of the soldering iron.
- Be careful not to use too much solder and bridge adjacent connections.
- Allow the solder to cool at lease five seconds after removing the iron.