Operating instructions

Fig. 420: 7 Day Digital Timer Model 1529
Fig. 421: 7-Day Digital Comfort Timer Model 1531
4.8.4 Sleeper Fan Wiring
A: Sleeper Fan is Cycled On/Off by Vehicle Thermostat
1. Turn ignition key to “ACC” position to power up sleeper.
2. Select desired temperature on thermostat and turn on sleeper fan to low position. Fan will cycle
On/Off to maintain temperature.
B: Sleeper Fan is Cycled On/Off by Webasto Thermostat
1. Install Webasto thermostat #129.560. Locate the thermostat in an area where routing of the wiring
is possible, about halfway between the ceiling and bed. Do not locate in direct air flow from the
heat exchanger nor mount to a cold surface.
2. Mount interlock relay near the heat exchanger.
3. Route one leg of the blower interface harness P.N. 905.663 from the relay to the Webasto heater
and the other leg to the thermostat and secure every 12 inches (30 centimeters).
4. Make wiring connections as shown in figure 422, sleeper fan wiring and figure 423, wiring diagram
- Thermo 90 S.
429
Thermo 90 S 4 Installation
CAUTION
Leave waterproof connector uncoupled until completion of installation.