check the fuse or the ground on the heater
Check the alt & idle speed.
Yes
bad fan clutch, clogged radiator.....................when you turn the defrost on, the heater core is acting like the radiator...............good luck, Mike
It's in the heater core housing.
Yes you can.
1986 to 1991
can I buypass the rear heater valve and run two heater 1986 gmc van
sounds like your heater core is plugged up with gunk install a new one
The cast of Ideas Unlimited - 1986 includes: William Woolard as Himself - Presenter
Loosen the dash and pull out the complete heater box after you have disconnected the heater hose from the firewall...........
Autozone
Could be 1 of 2 things: failed choke heater itself of 12vdc not getting to the choke heater. There is a relay (located on the RH fender wall under the hood) you should have 12 volt anytime the ignition is in run.