1977 Mark V Questions & Update

Bill,
I’ve never seen somebody so devoted to helping others with their passion. I truly love my Mark V and I’m glad to read so many helpful comments posted on your blog! You’re helping to keep these treasures rolling and all of us grinning.
Here’s my question:
The heat setting of my Mark’s A.T.C. doesn’t give me any blower function. I get great heat in defog but the fan shuts off only in Heat.
Where is the location of the C.E.L.O. on the 1977 Mark V with 7.5L? What other functions does this switch provide?
I also see some vacuum hoses going into what look like two ported vacuum switches, one directly on top of the thermostat housing and the other in front of that, by the distributor. What are the functions of those P.V.S.’ as well?
Dack
—————————————————————————————————————-
Hi Dack –
We are pleased that you enjoy the blog but it is more than just a passing interest for me. The blog is available for our already loyal customers and to further promote Lincoln Land in a way to develop our customer base.
The cold engine blower lockout switch on your 1977 MkV with the 460 cid engine is located on the intake manifold ahead of the carburetor. It is integral with the temperature switch. The plug is D shaped and the wire for the blower delay portion is yellow with a white stripe. If you have correctly diagnosed this as your problem, great ….but we find that this switch is rarely ever the cause of ” loss of blower” in the Heat position with a warm engine. If you are doing your own repairs and wish to diagnose this and learn about other engine controls such as the engine vacuum controls, a proper FoMoCo shop manual is a must as the vacuum controls can be confusing with the many designs during the model year. The manual explains many of these questions at length. Contact us if you need further information on your blower issue or if you would need any manuals.
Sincerely,
Bill
—————————————————————————————————————-
Bill,
I appreciate your detailed response. I couldn’t find this information anywhere on the Internet!
I’ve found the switch and it is functional. I’ve narrowed it down to the fact that there is low voltage to the primary side of the EVR solenoid. If I short the wires on the secondary side, the blower and ATC function normally! The Ford wiring diagrams sure don’t make it very easy to trace but it can be done in time.
Thanks!
Dack
—————————————————————————————————————-
Dack –
It sounds like you are on the right track now due to the correct diagnosis on your part. We of course have the necessary repair parts for you when you need them.
Bill