1996 Cadillac Deville 4.9L

How exactly did you bypass the Vats system?

Attached is the starting circuit schematics. The Red wire with power supply from the batt2 (30 A fuse ) should be the main power supply for the switch. It operates the dash indicator lights as well.

I measured the resistance on the key and placed into the wire. Well I think this car has a vats. My plan of attack is to remove all wires from the eng compartment tag them and pull through the firewall, then I will re-install all the wires to the eng compartment and slowly find where each wire goes. I have a photo of the disaster.
Thanks
Jim

That will bypass only the ignition switch sensor. The rest of the system must still be operational or the starter will be disabled.

How do I get this disabled, or should I run new wires?

You cannot completely disable the Passkey system. It HAS to be operational unless rewire the starter circuit. You may be able to make it work by permanently grounding the yellow/blk wire at the starter relay. That would enable the starter circuit but the Passkey system will also disable the fuel.

So can I rewire the fuel? I take it this system is in the ECM and if so can I put in a different ECM or would I be betterr to send it to the scrapper.
JimG

No, you HAVE to make Passkey operational and that may require a professional scan tool.

I do have a newer snapon scanner and it should work on the cad.

It may if it's updated sufficiently.

OK, well you did not tell me I was chasing a dead horse so I will give it a go, I am retired with not much to do. before I go do you have a schematic for the fuel and Vats system and what manual do you recommend

Here ya go. The PCM does all the fuel and starter controlling after receiving authorization from Passkey. The dash cluster is an integral part of the Passkey circuit also.

thank you and have a great day

thats how they build the 70s streach serises at the factory.its almost 2 feet longer wheel base. ok jim,you need to drop the column for better axcess to the ingition switch.before removing the 2 bolts holding the column. you need to remove the cable that goes to the prindle its on the shift bowl.use a screwdriver to release it.then remove the bolts.the column will drop down.the switch will be on top of column by the dimmer switch.red wires are constant power and pink wires are hot when you turn the key on. if you hold the key in crank it sends a start signal on the brown wire.ck. for that signal.with a test light if ok,it goes from the ingition switch to the neutral safety switch on the side of transmission and next to the starter.you dont need the resisstor for the vats unless the security lite is on.thank you for donatioins.gl,.

If any of that is going to work, you should be able to simply turn the key on and jump the starter solenoid and it should run. You might want to try that before doing all that column dropping. I guess we are assuming the security light even works.

he said it cranks from the starter and not the key wrenchtech.if he can sneek up under the dash and locate the brown wire and turn the key at the same time he checks for a start signal.he can do that too.

Your assuming there is not a Passkey issue causing this and before I would pursue that theory too much i would prove it out by jumping the starter and hearing it run. If it won't run that way, then there is more than a starter circuit issue.

this is true.just responding to what he 1st said. it turnS OVER FROM THE STARTER AND NOT THE KEY.SORRY CAPS. and he reads the key and gets the right resissor across the 2 white wires. guess we will see when he comes back.ltr wrenchtech

OK, here is where I am at this point in time well let me back up, I got stuck with the bid at auction the car or what is left of it has 12000 on the clock so I was told, for what ever reason the main part of the car was sawed of just behind the A-Pillar all the way across and thru the roof. All wires to the rear were sawed off so what I got was the front with Dash in place and the steering column with the key, no hood, fenders, radiator or A/C condenser.I was texting with a fellow triker and he said the part I needed to make this work was in the trunk. I put a bat in and tried to crank the engine and nothing only thing that happened was the anti lock brake came on I then saw a post about putting a resistor in the key circuit and again nothing. I dropped the column and removed the switch so I could work it manually and made sure the trans was in N. Right now I am working on removing the entire harness from the eng bay pulling it through the firewall and then reinstalling everything back to its original position, this will allow me greater access to the wiring and removing what I do not need. Sounds like a project but I am retired and I need something challenging and I think it would make one heck of a trike, but I need to find the wires that go to the rear of the car that I need.Wiring under the dash was not touched so it is intact also there are two ECM? on the right kick panel. So I appreciate all help.
JimG
Cushing, WI

You cut off a whole fuse box.

No I did not cut anything off, I bought the car this way and I am unbolting all the wiring in the engine bay pulling it through the firewall and then I will reinstall the wiring so it is easier and safer to work around, sawzall makes jagged edges, look at the photo. I spent most of the day working at reverse engineering the dash to make sure all wires and looms came apart with no damage, you can see in the photo where the wires are cut and the same for the right side.

I know it wasn't you that did it. there was a fuse box in the trunk.

That is what my triker friend said so now I must work around the problem which is not insurmountable just need to get a good schematic

No, you need the missing harness to the back to try to splice back in. That is your only hope.

Well that helps me make the decision to send this to the scrap yard and save me a lot of time. Hey guys thanks for the help and ideas but I think if it is not raining tomorrow I will load it on the trailer.

if there is no fuse panel under the dash it has to be in the rear. the 2 computers 1 is the ecm 1 is the bcm.youll have a hard time pulling a full rear harness at the junk yard. best bet is to have them pull it.and splice it in with shrink rap connectors.if u remove any harnesses u need to put masking tap on the wireing and write what componit it goes to. allways label gl

Well the car is on its way to the salvage yard as it was going to be to much work and scrap is at $200. a ton and cash is good.
Jim

Wish you had shown that picture first. It would have made all this much easier.

I posted a photo of it at the top of the post, when I was told it was a bit on the impossible side that told me to scrap it.

You're right. I missed that.