Tibo

iTrader: (15)

Background is that I had an interior that claimed my fully functional VATS/Pass-key module. I found a new interior wiring harness and acquired 4 Pass-Key modules so that I could still use Pass-Key system. They are all the same part number and from 90-92 F-body.

I hooked everything up and have med sure that everything works. I have +12 volts to the module at pins A1 and B8. I have a negative/ground at pin B1. I have a +5 volts between pins A6 and B2 and also at the end of their wire runs at the connector for the steering wheel.

I've removed the starter relay andI have a positive 12 Volts at both respective terminals of the starter relay when cranking. Leaving the relay removed I can jumper the hot wire input (yellow wire) to the output (green wire) and crank the engine. I removed the relay and tested it off the car with a relay testing harness I made and it works perfect. I can put the relay in place, disconnect the Pass-Key module to apply a ground to pin A3 and the engine will crank.

It would seem like the Pass-Key module wiring easily passes all of the tests and is functional. The module also passes all the normal sniff tests. The module illuminates the security light (which shuts off only while in crank) and sends a 5 volt reference to the connector at the base of the steering column.

I bought a resistor kit that had all 15 of the correct resistances that the VATS tables call for. I measured each resistor and they were all spot on or easily within the min/max deviations.

On to finding out which resistor operates which modules. I used an old steering wheel side connector and left a few inches of wire connected to which I crimped on some alligator clamps that held the resistor:



My method was to put in the first resistor and hook up the first Pass-key module. (The security light would then pop on and stay lit) I try cranking and get nothing. I remove the first module and start a four minute timer and then move on the the second module, then third and fourth. After they would all fail I would change the resistor and wait for the four minute timer to chime and then I would start the process over. I tried all 60 different combinations in total and I gave each module four minutes before retrying it with a new resistor. I also checked the voltage with the resistor in place and I of course was getting different voltages.

I am using an aftermarket ecm (MegaSquirt III extra) so the only function of the pass-key module is to ground the relay. This is not a problem with the vats in the OE ecm.

Not once have I gotten the engine to crank (or the module to ground the microswitch of the starter relay)

I am at my wits end. Could all four Pass-key modules be bad? Am I missing something obvious? Is there something I'm not trying?

I don't want to go without VATS because it's a great system when it works but I'm seriously contemplating just installing a small switch to ground the negative relay instead of further working on this.

scooter

iTrader: (11)

I don't normally bother replying without help to add, but why bother with the headache of the VATS? There are newer//better/modern security systems out there that are not difficult to install and less headache to troubleshoot. Especially if you're going to use the Megasquirt

With my overhaul, I installed a new security system that provides a ground when disarms, I linked that to the factory VATS location, so it works exactly like the VATS, but now I get the pleasure of passive keyless entry.

Tibo

iTrader: (15)

I actually have a keyless entry system on the car for the shaved door handles, I purchased another system last year that has an alarm on it that can have other secondary functions. I'll look to see if I can wire it with a grounding and ground removing function. Off the top of your head what are the other systems you might recommend?

scooter

iTrader: (11)

I know DEI has many alarm systems. I am using an Advanced Keys https://advancedkeys.com/ It's passive, so I just have to get close to the vehicle and it unlocks the doors. I stayed with the "base" system, so I still use the ignition to start the vehicle, but they also have an add on to work a push button start. Nice thing about this system too, I can use the same "fob" to work multiple vehicles, so it does my 92 Firebird and my 69 Suburban, and I will add the same to all my other car projects.

I have the "ground on disarm" actually in series with my NSS on the clutch pedal. Since I was converting from auto and adding the NSS I figured leaving the stock start enable relay was a good idea and the NSS will last forever since there is no "high current" going through it now, since it is just part of the ground path for the control side of the relay.

QwkTrip

iTrader: (22)

* Polarity matters. Did you make sure B2 is (+) and A6 is (-) ?

* And maybe test to make sure B1 is actually grounded to chassis. I think it grounds in the engine bay (same ground circuit as the Diagnostics connector). That can be easily forgotten when swapping in a harness.

Honestly, I was surprised when you said your VATS still cranked the engine without engine ECM. I was under the impression that engine ECM has to grant permission first, but your feedback is why I wrote the VATS thread the way I did.

Oh, and be sure to tell Drew and JT just how easy it is to steal a thirdgen by defeating VATS. In and out in 1 minute, right?

Tibo

iTrader: (15)

I did have the correct voltages for the pins you mentioned.

The only solutions that make sense are that all four modules are bad or that my stock wiring at 30 years old has more than the allowable deviation for resistance. I took to eBay and the web to see if there were any new or verified good Pass-Key systems and there aren't. They are all listed as-is without warranty. I had spent the last week on the Pass-Key system and I was just ready to move on so I took Scooter's advice and installed a car alarm that grounds the relay when turned on. The car starts now with the alarm disarmed. I removed the connector from one of the Pass-Key modules and soldered the alarm's harness to it so it's plug and play and I could go right back to the Pass-Key system if I ever wanted.

This week I'm going to try to verify if it's the wiring by using a short pigtail harness and hook it up to that Pass-Key module outside the car and then hook the resistor up to the harness so it only has to go through 4-6" of wiring. I'll just run a test light led off the negative wire that triggers the relay. If it doesn't trigger the negative wire they must all be bad.