Kim, I have the 88 that I think is similar to your 87. On my dash if you slide the temp control switch from left to right you will get cold or hot air. If you slide it all the way to the right it will turn on a water pump that is located in the front on the passenger side that will circulate the coolant throught the system. I have switches for compartment heat (lower bay) and rear heat (rear bedroom) which are on the dash.
I'm convinced that you have valves on the passenger rear near the lower portion of the engine that turns the coolant system on or off. They are two round valve handles and you have to open both of them for the system to work. Look on the fan end of the engine for the water lines and one is below the other. This system controls the bedroom heater, the compartment heater, the dash heater and the hot water heater.
Good luck, I think it's a real simple fix.
Wally
|