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'71 Eldorado: loose wire ID

Started by wbdeford, June 08, 2015, 07:57:25 AM

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wbdeford

Trying to figure out what this loose blue wire is (see pic).  It runs beside the brown alternator wire along the passenger side valve cover before both disappear into electrical tape behind the engine, with a mass of other wire.  My metal temp heat switch is missing its wire, so it could be to that, but I want to verify.  The reason I am uncertain is that the alternator wire goes through the fire wall, while the metal temp heat switch wire stays in the engine bay, so it would seem strange to bury them both in the same mass of tape.  But the color does match, so....
1958 Sedan de Ville

Past:
1956 Fleetwood 75 Sedan
1957 Fleetwood 60 Special
1958 Miller-Meteor Futura Landau Duplex
1960 Coupe de Ville
1966 De Ville Convertible
1970 De Ville Convertible
1971 Eldorado Convertible
1979 Sedan de Ville
1980 Seville

The Tassie Devil(le)

That sensor is for the A/C/Heater control so that the heater won't come on until the coolant is sufficiently warm enough to give heat to the occupants.

If there is no other wire floating around, then the loose one could be for that.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Scot Minesinger

Agree with Bruce, that loose wire likely goes to the male spade behind alternator and allows heat aspect of climate control to start when car is warmed up.  I routinely ground this by installing a double spade on sensor hooking up climate control female to one of the double male spades.  then connect the other double male speed to a good ground. 

There is also a sensor in dash climate control for cooling (to make sure a/c has a slight delay) and this often fails.  The grounding of cc allows cooling to always operate.  If dash sensor fails and sensor behind alternator is good, a/c will start after car is warmed up, which is often too long to wait for A/C.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

wbdeford

Yes, I thought it might be for the oil light since my oil light wasn't working, but found that at the back of the engine, and the bulb does work (need a new oil pressure switch).  I suppose I could try turning the heat on full when the engine is cold, ground the wire, and see if the heat kicks in.  I might just ground it semi-permanently until the time, if ever, I decide to fix the A/C--not a lot of value in auto climate control without A/C.   Compressor was already locked up when I got the car, so I removed it to get it out of the way.

Thanks, guys!
1958 Sedan de Ville

Past:
1956 Fleetwood 75 Sedan
1957 Fleetwood 60 Special
1958 Miller-Meteor Futura Landau Duplex
1960 Coupe de Ville
1966 De Ville Convertible
1970 De Ville Convertible
1971 Eldorado Convertible
1979 Sedan de Ville
1980 Seville

"Cadillac Kid" Greg Surfas 15364

William,
The device in question is the FAN delay.  Although the compressor will run (assuming it will run) any time the AC Selector lever is in any position other than "off",  but the fan control circuit will not be energized until the motor has warmed up (75-120 degrees) enough to have warm water for the heater.  This also serves a secondary purpose for the refrigeration cycle, so keeping this in the circuit is highly desirable.
If you find this sensor/switch to be bad they are available.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-