Subaru Legacy/Outback

1999-2003 of release

Repair and operation of the car

Heating of back glass and rear-view mirrors - the general information, check of serviceability of functioning of components, recovery repair of a thermoelectric heating element

General information

Heating of external rear-view mirrors joins along with heating of back glass of the car.

When transfer the switch of heating of back glass / rear-view mirrors there is a short circuit on the mass of the electromagnetic relay of a chain of giving of food to the corresponding thermoelectric heating elements. The indicator lamp of inclusion of heating is built usually in in the switch button, but can settle down and on an instrument guard. The relay of a heating system is in the saloon assembly block of safety locks/relay.

The working element of a heater of back glass represents a horizontal lattice from the conducting threads pasted on an internal surface of glass.

Check

Heating switch

Check serviceability of functioning of the switch of heating for what remove the control panel functioning of systems of heating/air conditioning. Disconnect an electrical wiring and check correctness of distribution of conductivity between plugs of the corresponding contact sockets from the back party of the panel in both provisions of the switch (see table 28).

Tab. 28 Check of serviceability of a condition of the switch of heating of back glass / rear-view mirrors

Thermoelectric heating element of heating of back glass

Turn the ignition key in the situation ON and include heating of back glass.

In order to avoid damage of conducting threads of a heating element wrap up voltmeter probes aluminum foil.

The voltmeter should be transferred to the mode of a direct current (DC).

Press the positive probe of the voltmeter to the positive plug of a lattice of a heating element, press the negative probe to the grounding plug. The device has to register battery tension, otherwise check a condition of a safety lock, the switch and a connecting electrical wiring. If tension in norm, however, part of the heater does not work, pass to the following stage of check.

Measure tension in the central part of each of lattice threads. The indication in 5 ÷ 6 V testifies to serviceability of a condition of a thread. The zero indication speaks about existence of break between the center of a thread and a positive side of an element. Overestimate of the indication twice (10 ÷ 12 V) happens in the presence of break between the center of a thread and a negative side of an element. Serially check each of lattice threads.

In the absence of breaks connect the negative probe to the mass of the chassis and repeat check, - indications should not change, otherwise violation of quality of grounding of a lattice takes place.

For localization of break press the negative probe of the voltmeter to the negative plug of a lattice of a heating element. The positive probe which is wrapped up by a foil start probing conducting threads of a lattice, moving from giving of food to weight. In a break point instrument reading has to reduce from several volts to zero.

Recovery repair

Restoration of integrity of conducting threads is made by means of special two-component electrowire paste like Dupont No. 4817.

Before starting recovery repair of a lattice of a working element switch off a heater and let's an element cool down within several minutes.
Slightly smooth out the damaged thread site felt, then carefully wipe it alcohol.

Paste two strips of an adhesive tape along the thread site which is subject to restoration. Carefully mix epoxy paste with a hardener (follow the instructions enclosed in a set). Apply the received structure on the damaged site (with an overlap approximately in 20 mm on edges of the intact thread).

Final polymerization of a compound happens in 24 hours after which protective strips of an adhesive tape can be removed from glass.