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1959 Cadillac CDV - Temp Gauge Problem

Started by Paul, July 24, 2018, 12:22:30 PM

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Paul

Hi All,

Wondering if I can get some technical opinions on a weird problem that surfaced on my car.  The temp gauge is not registering any movement at all. I tested the sensor in the engine compartment by grounding it. When I did this the Generator Light on the dash popped on? When I removed the ground, the Generator light went off. If is put the car into accessories mode at the starter, the only light that is on is the OIL light.  Two questions: What lights are supposed to come on before I crank the engine? Why would the Generator light come on when I ground the temperature sensor?  Any thoughts would be appreciated! Thanks.
59 Caddy, Seminole Red with Dover White top

J. Gomez

Paul,

You did not specified if your problem manifested after working normally or if it never worked correctly.

The only lights that would show on the instrument panel after you turn the key over to “IGN” without turning the engine on would be the OIL (if there is no oil pressure on the engine) and the GEN.

Is the wire at the temp sender on the engine “dark green”?

Maybe someone had cross the wires around between the GEN and TEMP either on the engine side and/or at the instrument panel?  ???

TEMP wire from the sender is “dark green” and it should go over to the left side plug behind the instrument panel.
GEN wire for the light is “brown” and it should go over to the same left side plug.

Now both are going to a junction box so that could be another point to check.

Good luck..!
J. Gomez
CLC #23082

Paul

Wires are in the right place on the engine side so I will pull the dash and check to see where the go and if they are crossed. I hope the gauge itself is okay. Thanks for your insight.
59 Caddy, Seminole Red with Dover White top

gkhashem

I thought all lights came on momentarily when you start the car as a test to confirm the bulbs have not burnt out. Then they go out after the car starts. Unless you have a cold light as on an Oldsmobile or other car. All my Cadillacs have a temp gauge. So no temp light.

I am almost 100% positive on this.
1959 Oldsmobile 98 Holiday Sports Sedan
1960 Cadillac Coupe Deville (CLC Sr #72)
1964 Oldsmobile 98 Town Sedan (OCA 1st)
1970 GMC C1500
1977 Oldsmobile 98 Regency Coupe
1978 Cadillac Coupe Deville (CLC Sr Crown #959)*
1992 Oldsmobile 98 (OCA 1st)
1996 Oldsmobile 98
*CLC Past President's Preservation

Past Cadillacs
1959 Coupe Deville
1966 Coupe Deville (Sr #861)*
1991 Eldorado Biarritz (Sr #838)

Paul

Just a quick update. I haven’t pulled the dash yet but I cleaned the sending unit and the wire with some sandpaper and reconnected. The temp gauge sprang to life. Looks like it was a dirty connection. I noticed the engine generally runs cool - any other 390 owners experience this? I still need to look at the wiring because grounding the temp gauge wire still causes the Gen light to go on when accessories are on before the crank. Got to find that crossed wire. I’ll update when I figure it out. Thanks for all the help!
59 Caddy, Seminole Red with Dover White top

59-in-pieces

Paul,
Same fix for the problem with your 6 way seat switch.
I detect a pattern here - crusty connections.

I have never seen a Seminole red with white roof before in the wild.
Please post a couple pics.

Have fun,
Steve B.
S. Butcher