Alarm System - False Alarm Activation

Service Bulletin
Cars

855/V70-2000/V70 XC
1994-2000

Section
3

Group
36

No.
0019

Year
01

Month
09

Rear windshield, alarm wire, repair

Background:

False alarms caused by an open circuit in the rear windscreen alarm wire may be due to a mixture of salt and water forcing its way between the glass and the washer nozzle seal and causing corrosion.

The open circuit can be localized using a ohm meter. The open circuit can be repaired using conductive paint. A template and brush are supplied when conductive paint is ordered.

If the false alarm is caused by corrosion, replace the washer nozzle with one with an improved seal. The method can also be used for repairing the antenna and heating loops on some rear windscreens. (See Service Bulletin 84-0014).

New improved washer nozzles were introduced from chassis number 711680.





Affected vehicles





Materials

Alarm wire, open circuit, repair

Localize the open circuit in the alarm wire 1

Switch off the ignition.

Remove:

- the panels on the tailgate, see VADIS:

Repair and installation instructions Function group 85 "Tailgate"

- the washer nozzle





Check for signs of any open circuit on the wires. Establish the position of the open circuit in the alarm wire (1) using a ohm meter.

Position the measuring pins on both sides of the suspected open circuit. If the resistance is near 0 ohm, the open circuit is not between the measuring points. Reposition the measuring points to identity the point of the open circuit.

Use tape to mark the position of the open circuit. If the open circuit exceeds 2 mm (0.075"), the alarm wire should not be repaired. In such cases, replace the rear windscreen, see VADIS:

Repair and installation instructions Function group 84 "Replacing the rear windscreen"

Cleaning and preparing the alarm wires 2





Carefully scrape clean the alarm wire each side of the break using the point of a razor. Take care not to increase the gap more than 2 mm (0.075").

Note!
If, after scraping the alarm wire, the open circuit exceeds 2 mm (0.075 ") in length, it is recommended that the rear windscreen is replaced. See the method in VADIS.

After scraping off any oxidation, clean the point of repair using window cleaner.

Installing the masking template 3





Secure the masking template onto the window with the slot over the alarm wire. If the alarm wire is narrower than the slot on the template, adjust the template to the correct width.

Repairing the alarm wires 4

Note!
Shake the conductive paint container well before use.





Apply conductive paint to the broken element three times at intervals of five minutes.

Coat approximately 5 mm (0.2") either side of the break.

Thinners can be used when cleaning (if necessary).

Note!
The paint on the repair has to dry for 30 minutes before removing the template.

Install:

- the new washer nozzle

- the panels

Checking the function of the alarm 5

Erase any diagnostic trouble codes (DTCs) that apply to the alarm system.

Carry out a function check of the alarm.

Close all doors and hatches, set the alarm.

The fault has been remedied if there is no false alarm and diagnostic trouble codes (DTCs) no longer remain.





WARRANTY STATEMENT: Claims may be submitted under the New Car Warranty when there is a documented customer complaint, using claim type 01.