No heat

co-worker's late 90's bmw 7 serie...740 ??

Blower works , but no heat......

Now what ??

Thanks.

Let's start simple. What does the temp gauge in instrument cluster show? Is the needle at 12 O'Clock or on the cool side? If yes then I would suspect a thermostat failed in the open position. Barring that, the auxiliary heater valves, on firewall and adjacent to the expansion tank (drivers side could be bad. Do you have a Bentley manual, if not I would buy one, I find it invaluable. Aslo, check the 7 series message board and archieves at roadfly.com