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Engine Swap information - keeping your lockup cruise and AC

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  • Engine Swap information - keeping your lockup cruise and AC


    Originally posted by DoubleV
    There's 2 black connectors that plug into a clear/white connector near the ECM. The clear/white connector is part of the ECM harness and this entire harness can be removed. When you remove this ECM harness, the 2 black connectors and all the wires that go through the dash will still be there.

    Look at the 2 black connectors. They are lettered. Pin 'M' should be a black wire with a white stripe. This is the ground for the 'Vechical Speed Buffer' which is needed for cruise control. Just ground this wire and you'll retain cruise.

    Pin 'P' should be purple. Get a Painless converter lockup kit and run it to this wire. You'll have converter lockup without even having to bother with the included brake switch from the kit because the G-body's already have it and it's allready wired up for you from the factory. This is why you just have to hook the Painless kit ( a purple wire ) to pin 'M' ( a purple wire too ).

    Pop the circuit board out of the 'remote lamp driver' ( greenish colored plastic box wired into the ECM wires going through the dash and located behind the glove box ) and this will make the 'Check Engine' light go out.

    With the ECM harness it depends on wether you want to remove it intact or in cut into 2 peices.

    To remove it intact, do this;

    1) Remove front passenger side wheel.

    2) Remove a total of 3 bolts from the plastic inner wheel well ( the ones that allow you to pry it away and give you access to the grommet in the firewall where the harness goes through ).

    3) Pry plastic wheel well as far as you can. Wedge a small block of wood in there to keep it out of your way.

    4) Remove 2 small screws for the bracket that holds the grommet secure. I think they were 7mm???

    5) Pry grommet out of firewall into engine compartment and the wiring harness will come with it.

    6) Plug up hole where grommet was. I personally used a spare grommet and still have wires routed out through it ( the purple 'P' wire for the lockup, and the pink/w black stripe 'E' wire for electric choke, and my 'M' pin is grounded inside the car just above where the ECM was located ).

    Obviously you need everything unplugged to and from the ECM harness to remove it, so above assumes you did so. Some of the bolts can be a pain to get to.

    If you want to do it the hackers way, just cut the harness somewhere and pull the 2 halfs out; one half trough the engine compartment and the other half into the interior.

    Getting your A/C to work without the computer is easy too, but my car has a different A/C wiring setup than yours, so I won't comment on that other than to say it requires nothing more than perhaps splicing a wire or 2 together. Worry about that when the time comes.

    With all this being said, as long as you're having no issues with your current CCC system and parts ( like the carb ), retaining it on your 403 is a pretty good idea and will cost you nothing since you already have it.

    My A/C is wired just like the one in your link with the addition of having the WOT cut-out switch ( which I think is cool ):

    What I did on mine though was not jumper the relay, but actually splice the black/w green and black/w white wires together. Also, I popped out the lt green/blk and the lt green wires that both go to the same terminal on the C497 connector out. Doing this removes the relay, the extra relay wiring, and the 2 prong C105 connector that hooked to the ECM. Things look alot cleaner there now.

    The VIN Y A/C is routed completely different at least on some years. Not sure why GM had so many different A/C wiring configurages though.

    P.S. If the A/C compressor was controlled by the ECM, then why did some years ( like my 85 442 ) need a WOT cutout switch on the gas pedal in addition to that? The ECM could've just turned off the compressor when it sensed WOT from the TPS.
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