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Discussion Starter #1
I'm currently helping my younger brother rebuild his wrecked 98 marquis. The front took a pretty hard hit and deployed the airbags, but didn't cause any frame damage. It did sever some of the wires in the harness that runs along the front of the vehicle, but I've repaired all of them. We've got a lot of it pieced back together, but we're having an issue with the fuel pump and ignition system not wanting to work. It acts like the PATS system isn't allowing them to kick on, but the light on the dash isn't rapidly blinking like I've read it does from other posts. The radio isn't getting any power as well, in either the "run", or "accessory" position. The only thing that seems to function in the "run" position is the climate system. The starter motor does work and will crank the engine, but I'm getting nothing from the fuel pump.

The fuel cutoff switch in the trunk wasn't tripped, BUT, the fuse was blown to the pump. I replaced it, but had no luck. I am able to jump the fuel pump relay, and can definitely hear it running, but the car doesn't want to send power to it. I've checked multiple ground wires to the ECU and appear to be getting power, but something just seems off with the PATS. It does the 2 second blink when the key is off, and when I turn it to the "on" position, it continues to blink every 2 seconds, as if it's not even noticing the key has turned.

I'm wondering if the PATS system did some kind of reset and no longer recognizes the key. I don't know how long information is stored, but the battery was disconnected for weeks until we got to work on it. The fact the dash light isn't rapidly blinking in the "on" position is what seems weird to me, though...

I wanted to ask here if anyone has had this issue, and if there's some kind of reset one can do with the PATS, or if this perhaps some other electrical thing I'm missing.
Thanks.
 

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The first thing I would do is check for codes. Pats could be tripped and will throw a code if thats the case.


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Discussion Starter #3
The first thing I would do is check for codes. Pats could be tripped and will throw a code if thats the case.


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Ah, so it'll throw a code? Didn't even think to try that. I'll have to borrow a scanner tomorrow and check it.
Thanks!
 

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Ah, so it'll throw a code? Didn't even think to try that. I'll have to borrow a scanner tomorrow and check it.
Thanks!
If pats immobilizes the ignition a body code will be thrown.


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Discussion Starter #6
So I borrowed a friend's code scanner, and couldn't get any reading. It would power the scanner, but would not communicate with the computer. I went and jumped the EEC relay and managed to get the scanner to actually communicate, but it didn't list any codes. I also heard (I believe) the injectors "sing" when I jumped this relay. It might seem crazy saying this, but I swear it sounds like they play a little 2 second tune of sorts when you do that.

Even doing this, I'm not getting any change to the PATS light blink. Also still have no power to the fuel pump unless I also jump the relay for that...
It's such a strange issue, but I have a feeling it's possibly a bad wire somewhere. Perhaps the ignition switch could be bad, but the climate system comes on, and the starter works too, so I dunno. I'm going to check over the harness again and maybe check continuity across the plugs.
 

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It does sound like the ignition switch. Usually the switch seperates, the plastic from the metal, so it would be wise to remove the steering column shroud and take a look at the switch.


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Discussion Starter #8
Alright, some good progress now.

I threw a new ignition switch in and also noticed a 50a fuse was popped, so I swapped that out too. I didn't notice it until I actually pulled it out and saw the crack across the link. Now I've got the radio back and the chime is chiming away as it should. PATS system light goes solid, then proceeds to give me a code 16. After doing some digging, this seems to be a communication/power issue with the PATS/ECU. Many suggest the "EEC relay" is the cause here. I swapped it out with a couple of other relays, but still can't get it to stop the code 16 blinking. Interestingly enough, I can jump the EEC relay and the blinking stops. The engine will actually start and run by doing this, and all seems to be normal... but I know it's not good to just leave that relay constantly "jumped" and on. For some reason, I'm guessing I'm not getting a signal TO that relay to click on from the ignition. When it's "jumped", everything seems to function as it should, and the PATS doesn't act up.

Guess I'm gonna dig some more and see if there's a wire or fuse I might've missed to this relay.
 

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Discussion Starter #9
WOW... okay I'm stupid and overthinking things again. The small gray jumper relay I've been using to jump the bigger relays wasn't plugged back in. I thought it was just a tool that rested in the box as a way to test continuity and relays, but I see it actually provides power to the rest of the relays after flipping the box over and seeing the wires. Now that it's plugged in, everything it working as it should, and the PATS is happy.... Jeeze.

Still, that 50a fuse was bad, and I'm pretty sure the ignition switch was gone, or going out, because it feels a LOT smoother than my old one. Thanks for those that chimed in!
 
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