Heater operation

[Rwsjr]

Working on my second Fiat since I had a 1300 roadster in 1968. Acquired a 79 124 spider that had been sitting for 5 years. I typically take on British cars so I am ignorant at times on the Italians. I have followed recommendations and gone to a 1600 intake, a weber 32/36 I had left over from an MG and no cat. Plenty of pep so now I would like some heat. What heater control positions should I use? Seems like I have tried all combinations with no result. Is there a heater fan or is that what fiat calls the defrost fan? Are the heater valves or heater core problematic and probably the culprit? Thanks for the help

[azruss]

first the controls. the lever on the drivers side controls the fresh air intake (this is the flap under the cowling). All the way up is full open (fat end of triangle). The middle one controls the coolant thru the heater core. All the way down is full open (fat end of triangle). The far right controls a flap that allows heat to the floor. when closed the heat goes to the 2 ports in the dash that defrost the windshield. Your control should be marked "def" on the full up position. So full heat is left up, middle down, right down.
Valves are an issue as they leak and require replacing. Not a big job, but the modern valves dont fit the car. Mr. Allison as come up with a fix for this. will be worth the money if you need to replace the valve. Heater cores are like radiators so can develop leaks. They are brass, so more durable than a modern radiator. to remove or inspect requires removal of the upper console. Look to see if the heater lines from the engine are connected. look on the firewall just to the left of the motor and you should see 2 rubber hoses about 1" in size going into the firewall. If they are there, then the system hasnt been messed with.

[RRoller123]

That first lever may possibly be inoperable which wouldn't open the flap and let enough air in to be effective. You can check under the windshield cowl to see if the flap opens and closes, just be careful not to scratch the fenders, and while inthere, a refurb of the WW mechanism is in order too. Here is under cowl pic:

[Rwsjr]

Thanks folks, I really appreciate the help. Let me know if you have problems with old British sturr..MG, Triumph, Sunbeam, Jag.