Lamp unit fogged or droplets forming.

Because of the housing cover with pressure compensation membrane, the lamp unit is a “closed system”. This means that the lamp unit is protected against acid gases, dirt and exhaust gas. However, moisture can still enter from two sources.

Through absorption and desorption (the commonest cause) or through permeation.

Moisture is either absorbed by the plastic material and, when the light source is switched on, it is released from the plastic by desorption, or the moisture penetrates through the plastic materials of the headlamp from outside (permeation).

This can lead to the formation of condensation on the lens of the headlamp.

Check housing cover of lamp unit for natural fogging or condensation and perform leak test as per LI82.10-P-050151.

.

If no reduction in the degree of fogging is visible, the lamp unit is defective and must be replaced.

On the new lamp unit, the service cover with desiccant pack must be installed.

Since the replacement headlamps are not supplied with control units, use the control units from the headlamp with condensation.

Make sure that the contacts of the old control unit are undamaged and dry.

.

Note:

Residual fogging is possible due to the laws of physics and is OK.

Fogging does not impair the functionality or the service life of the lamp unit.

Desiccant packs must always be used in both lamp units.

.

1. Remove existing service cover with membrane [Figure 1 (1)].

2. Place desiccant pack [Figure 1 (2)] in new service cover with membrane and close with protective grille. Screw down the protective grille with the screw provided [Figure 1 (3)].

Note: One desiccant pack is required for each headlamp.

3. Stick the membrane supplied onto the new service cover and attach to the headlamp.

Note: The bonding surface must be clean and dry.

4.      If the headlamp housing has an additional 2nd membrane, this must be covered over with the masking tape.

Note: The bonding surface must be clean and dry.

.

To ensure that the drying pack (absorption) acts effectively, the headlamp has to be air-sealed.

Observe or check the following points for this:

1. The seals on the central connector must all be present [Picture 5 (1)] and correctly fitted [Picture 5 (2)].

2. The new transparent diaphragm must be correctly bonded [Picture 6].

3. Check headlamp housing for any external damage.

.