TCCoA Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
hello I have a 91 ford thunderbird sport 5.0 the vent controls wont work ive looked for the vacuum and fixed the ones that were broke. also my heat wont wont work when I turn the heat on defrost its cold air. can anyone please help me it getting cold out lol
 

·
Super Moderator
Joined
·
4,923 Posts
Step one - pick up a copy of the EVTM (Electrical Vacuum Troubleshooting Manual) for your car from either Helm Inc. ( www.helminc.com ) for a new one, or from Ebay for a used one.

Step 2 - Do the heater hoses get hot, both of them, when you turn the heat on? If so, it's possibly the blend valve (which can be vacuum). If not, you may have a plugged heater core.

Step 3 - After you get the vacuum fixed, see if the temp works right. And if it does, there you go!

RwP
 

·
Registered
Joined
·
7 Posts
Discussion Starter #3
i took off the glove box and when I looked behind it there is a white black red and blue connector just sitting there where does this plug into.. getting very frustrated with this problem
 

·
Super Moderator
Joined
·
4,923 Posts
That should plug onto the back of the control head, if you've got the non-EATC heat/cool system (no LEDs, knob turns to set fan speed instead of a slider)

Which would explain it - black is vacuum from the motor (and I bet you have some minor problems with running lean too!), blue and red go to the panel/floor control, and white goes to the outside/recirc control.

This won't help the no-heat, but at least you'll fix the problem with the vents.

Now, if the head is disconnected, there's a chance the control cable to the temperature blend door is disconnected.

This is all from page 52-1 in the EVTM, BTW.

I'll recommend again that you should pick one up, it makes working on these beasts a LOT easier.

RwP
 

·
Registered
Joined
·
7 Posts
Discussion Starter #5
I fixed the vents!! Still no heat, someone told me that my clutch fan is bad and thats why i have no heat?i am purchasing that book tomorrow! But very happy i got the vents working thank you for the help
 

·
Super Moderator
Joined
·
4,923 Posts
No heat, but the car doesn't overheat, is usually a plugged heater core.

Sounds like time to reverse flush that core.

Also, check. If this car sprung a leak, a previous owner may have bypassed the heater core.

But, no, the clutch fan being bad won't cause no heat.

OH! Be SURE to change the sending unit for the temperature gauge! There's a TSB on them failing, causing the gauge to read LOW on our cars (the 5.0HO in the 91-93 MN12s.)

RwP
 

·
Registered
Joined
·
7 Posts
Discussion Starter #7
how would you go about flushing it? I undid both the hoses took a water hose through it for a minute very little antifreeze came out one of the hoses are hot and one is normal.

are you saying the temp gauge is only like that in the manual? I have aod
 
1 - 7 of 7 Posts
Top