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97 Deville Headlights won't work

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Hey Guys,

Bought a 97 deville recently and pushed it into the garage. Needed a good detail and some minor repairs. However, for some reason I cannot get the headlights to work at all. I have replaced the switch, bulbs, fuses and relay.(Underhood Relay) If I take out the underhood relay and jump the org/blk to either the tan or green wire, I get lights. I know for fact the fuses and bulbs are good.

According to the wiring diagrams in Chiltons and Haynes, there is a second relay. I have pulled out the back seat and checked all 11 relays there. None have the corresponding wire colors that they should. As a matter of fact none are even close.

Forgot to mention earlier, the car does not have DRL, and when the switch is pulled on manually or the twilight sensor is on all the other lights work, parking, stop, tail, turn, and hazards.

Now for my questions: Where is the other relay? Is there something very obvious that I'm missing? With the light switch on, should I be getting power from the blue connector in the underhood relay? as of right now there is now power to the blue wire switch on or off.

Please help me.....What little brain I have is really starting to hurt!!!

Thanks for your time!!


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To begin with, you can't count on Chilton or Haynes and other schematics 100%. You really need a factory shop manual (FSM) for these kinds of things, and you can't do without one if you are going to maintain the car yourself over an extended period of time.

Second, run the OBD II codes (directions at the link in my signature block), write them down, and post them here; that information will likely tell us what is wrong.

The FSM schematics on page 8A-100-1 show that the headlamp dimmer switch runns from the 10 Amp MIRROR fuse in the engine compartment fuse relay center. The schematics on pages 8A-100-2 and -3 show that the headlamp relay, in the engine compartment relay center, is wrapped up with the park lamps relay in the turn compartment relay center #2. Then, there's a high/low beam headlamp relay in the engine compartment relay center; if this relay is bad or missing you won't have headlights.

There are four headlights fuses in the engine compartment fuse & relay center: L HDLP LO, R HDLP LO, R HDLP HI, and L HDLP HI, all 10 Amp.

An interesting thing shows up on the schematic on page 8A-100-6, for the Deville headlights: all four headlight grounds are through splice S107 to ground G101. The ground and splice S107 are hooked to lots of things, so if everything else works OK then the thing to look at connectors C103 and C104, which hook up the headlight grounds -- and the headlight power. These plugs, one on each side, are found by following the wires back from the headlights. If someone was working on the car they might have unplugged the headlights and, not driving the car, might not have noticed that they didn't plug them back into the wiring harness.

-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Jim, "You Da Man", I was so caught up in finding relays with proper wire colors, I didn't pay really close attention to the wiring itself. I was sure the fuses were all good, because I jumped the terminals on the High/Low relay umder the hood, that got lights. Anyway, went back to the relay center behind the rear seat, relay center #2, and was looking for the parking lights relay, when Viola'!! Broken white wire, maybe 22 guage, stripped it connected it and we are back in action!! Thank you so much. You got me looking in the right place, that was HUGE! Have a great night and thanks again.

PS: Fear not I'll be back with more questions.


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Most people will see that some time and patiennce along with generous forum members can help more than anything. Glad to see your problem has been solved.

Cadillacs are not at all alike, I have seen two of the same year cadillacs with very different setups, Security, Entertainment, Etc...


Nice, clean, luxury= fine automobile

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I do thank one and all who take the time to read the posts and offer advice. People here have always been helpful and friendly. I have learned alot here and am willing to help as my experience with the newer Caddys grows.

To one and all thanks again!


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