Intermittent engine not starting with a flashing security light?

Tiny
JORTMAN927
  • MEMBER
  • 1997 CADILLAC SEVILLE
  • V8
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
So, the car is not starting sometimes when I go to crank it, it has a flashing security light. Sometimes it doesn't, there is an orange park light and whenever I crank the key to the run position like to crank the engine, it does not start. I have checked the keys resistance and I have checked it is getting resistance to the orange wire below as I can still start the car using the relay the starter relay. I have no radio, I have no power windows, no moonroof, nothing. The key fob still works for unlocking and locking doors and the radio still runs in the accessory position and there's one small spot in between the on position and the start position that the radio still works. When I get it running it did not originally have the alternator charging but everything else ran it even drove perfectly fine the alternator just didn't charge the battery. So, I rewired that now the alternator charges the battery whenever I started using the starter relay, but when I have it started it has absolutely no power to basically anything except for basic necessities like fuel pump spark plugs etc.
Saturday, August 12th, 2023 AT 1:29 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

I suspect the ignition switch is faulty. I'm basing that on how the radio works when the switch is in a specific position. It could even be related to an adjustment issue.

I have a question. When the radio starts to work, do the other electrical components?

I attached two pics below showing the switch. When you turn the key, a pushrod moves the switch. You may want to check if it is loose or damaged.

Let me know.

Joe

See pics below.
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Saturday, August 12th, 2023 AT 9:53 PM
Tiny
JORTMAN927
  • MEMBER
  • 4 POSTS
When I turn it in between the run and crank position only the radio comes on. When I have it in the run position, you can hear the fuel pump start running, but when I turn it to the crank position everything turns off. I can still use the key to turn off the car as well and no matter what I do I get no power to my power windows, my sunroof, or my instrument cluster. Not even in the accessory position and when I turn the key to the crank position the security light starts flashing.
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Saturday, August 12th, 2023 AT 11:23 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

Both the power windows and sunroof get power from a circuit breaker in a fuse box under the hood. Both get power when the accessory time delay relay is actuated.

Here is what I think is even more interesting: The primary side of the relay gets power from the phone/radio fuse.

Take a look at the pic I attached and let me know your thoughts. We may have a faulty relay, or the circuit breaker may have failed.

Let me know.

Joe

See pic below.
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Sunday, August 13th, 2023 AT 9:16 PM
Tiny
JORTMAN927
  • MEMBER
  • 4 POSTS
So, I have checked all the fuses and they are good but I will definitely check these out in the morning and let you know. But even if they were out would that keep the car from starting at all using the key as well as none of the instrument panel working except the light for which gear I'm in and the security light flashing?
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Sunday, August 13th, 2023 AT 11:31 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

No, these won't. But I am trying to narrow things down. Let me know what you find or if you have other questions.

Take care,

Joe
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Monday, August 14th, 2023 AT 10:05 PM

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