Hi, I'm looking for a heater control unit for a 1986 chyrsler New Yorker or suggestions on how to repair it. Also the dash lights work sometimes but not always. Has anyone else experienced this problem and how to fix it.Thanks,Bruce in Ontario
a few things... and we should probably move this over to automotive.com instead of carcraft..click my user name for a link..just what are the issues with your heater control unit..does it just blow cold..can you verify the functions work..change the positions of the controls and see if it responds..defrost.. blowing air out at the windshield..face... air comes out the dash vents..floor.. air comes out the foot vents.. then do the same 3 tests to see if the temp shifts from cold to hot..if it does not work.. . you could have a vacuum issue.. where the ac control system is not getting supplied vacuum so it will change the position of the actuators...this all starts under the hood. these cars have issues when people have removed the thermostat.. they also have issues with CLOGGED HEATER CORES.. and bad heater control valve...the heater control valve has the engine cooling system thermostat bypass built into it.. when the heater is OFF... the heater control valve allows coolant to circulate straight thru it and back into the engine.. so there is coolant flow past the thermostat.. or it will never open..when the heater cores get clogged... turning on the heater will restrict the coolant flow and cause the engine to over heat.. as the thermostat bypass circuit is now directed thru the heater core.. if its restricted or blocked.. you will look a head gasket or crack a head..you will also want to pull the radiator cap.. there is a disc in the middle. if it dangles.. find a different radiator cap.. with a spring loaded version..
as for the instrument cluster illumination lights flickering..i would start at the instrument cluster fuse.. do you still have the owners manual to identify the location of that fuse.. instrument cluster power is complex..starts usually at the tail light fuse.. thru the headlight switch resistor.. thru the instrument illumination fuse. then up to the cluster..you can check that fuse with a test light.. see if the voltage varies when you have the headlights on and are probing the fuse.. then the fuse contacts.....
Wayne, thank you so much for sharing this with us.