900 L4-1985cc 2.0L SOHC (1988)
Rear Defogger: Technical Service Bulletins
Radio - Interference When Tuned to Weak Stations
CATEGORY
Electrical
SECTION
3
PAGE
41
ISSUE
04/93-0328
CODE
346
Subject:
Open Circuit in Electrically-Heated
Rear Window and Radio Interference
Application:
All 900 and 9000 Models
A complaint of poor reception when the radio is tuned to weak stations may be due to microscopic cracks in the electrically-heated rear window's heating
wires. Such microscopic cracks may cause electrical interference when the electrically-heated rear window is switched on, and this may affect radio
reception. While listening to a weak radio station turn the rear window defogger "on" and "off" several times and see if you can detect a difference in the
background noise. If you can, proceed as outlined below.
Cars Affected:
All 900 and 9000 Models
Parts:
Electrically-conducting paint (may be obtained from a local vendor, such as, Radio Shack) Voltmeter Flexible plastic ruler or equivalent substitute Razor
blade
Action:
1.
Connect one of the voltmeter leads to the ground (negative terminal) of the electrically-heated rear window, Figure 1.
2.
Switch on the ignition and activate the electrically-heated rear window.
3.
Start by taking a reading in the center of each heating wire.
The voltage indicated should be half the battery voltage. If the reading obtained differs by more than 3 volts from half the battery voltage, there is
a crack or other damage in the heating wire tested.