Opel 1900 1973 Service Manual page 88

Car &s out of gas with
gauge indicating fuel in
tank. 1
Temperature gauge not
hot when engine temperature
normal.
GAS GdUGE TROUBLE DIAGNOSIS - GT
An inoperative gas gauge reading can normally be
found to result from a poor grounding condition
within the circuit. Using the procedure as outlined
below may lead to the correction of the inoperative
reading without replacement of either the tank unit
or the dph unit.
1. Makelcertain the gas tank (ground) strap is prop-
erly secured.
2. Make'certain the ground wire (brown in color) for
gasoline/ and temperature gauges is properly con-
nected tb the windshield wiper motor and is secured.
(This gl?ound wire is also common for the heater
blower etor.)
If the adove procedure does not produce a satisfac-
tory gaube reading, an attempt to isolate the defec-
tive par<, i.e. tank or dash unit should be made.
3. Rem&e a tank unit from parts stock.
Possible Cause
1. Tank unit misadjusted
2. Defective voltage
stabilizer.
1. Loose dash gauge
attaching nut.
2. Defective temperature
sending unit
3. Open wiring.
1. Incorrect temperature
sending unit
2. i>efective temperature
3. Dkfective voltage
stabilizer.
4. Disconnect the tank unit lead wire (light blue with
black tracer) from the tank unit.
5. Connect ihe stock tank unit; ground unit, and
operate manually.
6. If the dash unit shows a correct reading, then
replacement of the tank unit is required as the cor-
rection.
A correct reading will be one which resembles the
movement of the manually-operated tank unit.
7. If the dash unit does not show a correct reading,
then its replacement is necessary.
M A J O R AEPAIR
Removing Voltage Stabilizer
1. Remove instrument cluster housing assembly.
GAUGES
Correction
1. Follow corrective action as
stated above (obtain empty
reading on dash)
1. See corrective action above.
1. See corrective action above.
1. Install 40 ohm resistor
between temperature sneding
unit and ground (disconnect
from unit). If dash unit reads
full scale, replace temperature
sending unit.
1. Follow corrective action as
stated above (connector socket
with blue wire).
1. Check for correct sending unit
(white porcelain) replace if
incorrect.
1. See corrective action above.
1 I- 67