Maniac (Heat doesn't work)

Old 01-29-07, 08:18 AM
Thread Starter
Join Date: Jan 2007
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Maniac (Heat doesn't work)

I have a 1991 Pontiac Sunbird, and I have replaced the water pump, temp. sensor, temp. sending unit and thermostat. My heat still doesn't work. Can someone help me figure thisout?
Old 01-29-07, 08:59 AM
Join Date: Jun 2006
Location: United States
Posts: 2,270
Upvotes: 0
Received 25 Upvotes on 24 Posts
Check the hoses going through the firewall to the heater core when the engine is warmed up they should be hot/warm if they are then you have a problem with either heater core or controls, if they aren't you have a circulation problem and you will have to backtrack the hoses until you find where they get hot and fix the blockage. Check all the associated fuses etc. Have a nice day. Geo
Old 01-29-07, 02:28 PM
Join Date: Oct 2002
Location: Hamilton County, Ohio
Posts: 3,927
Upvotes: 0
Received 2 Upvotes on 2 Posts
There may be a mode valve and mode valve motor. It should be vacuum operated, so check for vacuum leaks. This would normally shut off the flow to the heater core when the air conditioning is running. If bad, could keep the warm water from circulating thru the heater core.

Thread Tools
Search this Thread
Ask a Question
Question Title: