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Brake switch mod for 72 Cutlass

Old 06-12-2012, 10:46 PM
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Default Brake switch mod for 72 Cutlass

What are you guys doing for you brake switch for your swaps. I want to add cruise when I do my LS1/4L60E swap into my 72 Cutlass, and I heard you will need to switch or mod your brake switch. Some people use a relay but I have seen some take a brake switch from a newer Camaro or other vehicle. What Vehicles can you get one from that will work for a 72 Cutlass? This Camaro one looks pretty similar to my stock on except for the extra connectors. Are these much simpler to swap in and rewire? Thanks in advance.
Old 06-12-2012, 11:01 PM
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When I added cruise control to my 66 GTO I used a AC Delco switch part number D850A it is identical to the brake switch I have in my 69 chevelle except for the extra set of terminals, I am sure it will work in your 72 Cutlass as well.
I got it from Amazon for around $10.00 it is a direct fit and has 2 set of terminals, 1 set of terminals is normally open for your your brake lights and the second set of terminals is normally closed for your cruise control dis-engagement.

Last edited by lizeec; 06-12-2012 at 11:07 PM.
Old 06-12-2012, 11:01 PM
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I was able to swap in the switch from an 02 Z28...i think that is the same one you have picture. I am not using the Cruise Control. But I was able to just swap it, just about a direct replacement. I wired up the Brake Light switch and use one of the other sets pin for the TCC.

But as you note. I just added the correct terminal for the TCC and build a short harness to convery the terminal/pin for the Brake Light. I will have to use some relay to make sure I give the PCM the correct ground or power. If you research you will find what other have done. there is a sticky on connecting the Cruise Control.

follow my link in my sig for my Nova project, Page #5 and post #85.

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Old 06-13-2012, 01:40 AM
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Mid 80s GM brake switch for auto, available at Autozone. One terminal NO (brake lights), the other NC (TCC/cruise).
http://www.autozone.com/autozone/acc...er=612872_0_0_
Old 06-13-2012, 09:45 PM
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With the 6 pin switch, you would wire the TCC and IGN(12V) to one set of rear pins but do you know if you would wire the cruise with the TCC wire on that pin or use the other pins for cruise and IGN? And is it IGN(12V) that you would pair with cruise just like the TCC?
Old 06-14-2012, 03:31 AM
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You need a 4 pin switch. NO for the brakes, NC for the TCC.
http://www.lt1swap.com/
Old 06-14-2012, 06:51 AM
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I'm using the switch from a '96 Camaro (4 pin), drops right in and just need one wire for cruise or TCC, easy peasy
Old 06-14-2012, 09:49 PM
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So looking back at some wiring diagrams, there is a LT Blue wire that goes to the brake pedal switch for a +12v signal for Cruise to work, you tie that in with the Lamp side of the N.O. Brake Lamp section of the switch so it will receive voltage when you press the brake pedal. Is this right?
And to hook up the TCC, you use a +12V keyed source to on terminal on the N.C. side and then the TCC wire to the other terminal? I'm going to go to a Salvage yard this weekend and look for a 4 pin brake switch. If I can't find it I'm going to stop by the AZ by work and order one.
Old 06-14-2012, 10:30 PM
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4 pin brake switches are super easy to find in the junk yard, just about every GM vehicle from the early '70's to late 80's that has cruise control will have one. The old square body S-10's almost always have them.
Old 06-15-2012, 05:52 AM
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Are you running cable or DBW TB?
Old 06-15-2012, 11:25 PM
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I have a DBW TB
Old 06-16-2012, 06:30 AM
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There are 2 hookups at the brake switch needed for DBW TB.
NO goes to the brake lights and the TAC module (pre 07).
NC goes to the TCC pin on the ecu.
Old 06-16-2012, 06:49 AM
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Originally Posted by garys 68
There are 2 hookups at the brake switch needed for DBW TB.
NO goes to the brake lights and the TAC module (pre 07).
NC goes to the TCC pin on the ecu.
The NC side will also operate the cruise. Cruise needs a 12V signal through the NC side to stay connected and when you press the brake pedal you lose the 12V and cruise kicks out.
Old 06-16-2012, 07:26 AM
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You can wire it that way. Mine is cruise power is hot all the time with ignition on. Activation of the NO or NC switch to the TAC or ecu will kick the cruise off.
Originally Posted by LS1MCSS
The NC side will also operate the cruise. Cruise needs a 12V signal through the NC side to stay connected and when you press the brake pedal you lose the 12V and cruise kicks out.
Old 06-17-2012, 02:03 AM
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The wiring schematic I found says that the LT Blue wire from the TAC is for Stop Lamp Supply Voltage. Does that mean it is NC and the circuit is complete when brake pedal is pressed? If thats the case then you wire it with the TCC wires.
Old 06-17-2012, 03:29 AM
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see my post #12
Old 06-17-2012, 07:18 AM
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do you even need the tcc wired if your not using cruise on a manual?
Old 06-17-2012, 03:32 PM
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Thanks garys 68. I'll hook it up that way. I picked up a 4 pin switch from an 82 blazer yesterday. I also found a universal cruise control switch from a late 70's Ford that mounts on top of the turn signal lever. Is there a way to find out if its a NO or NC switch? I read that it makes a difference.

kevmac- TCC(Torque Convertor Clutch) switch is only for auto's. You don't need it wired if you have a Manual but you should need the Clutch Switch wires if you want to have cruise.
Old 06-17-2012, 04:18 PM
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thanx, try a multi meter on your pins and know for sure
Old 06-17-2012, 04:31 PM
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Bad news, ford uses NC cruise control switches. The GM ecu needs NO switches. I bought a generic from Dakota Digital and found out the hard way. You can wire with relays or try to find a GM that will work for you.
I used the DD ford style switch. Turns out there is a momentary closed lead from the resume wire when you hit set, if I remember correctly. So I wired that to the "set". The only functions that work on the stalk are the on/off ans set, but I'm ok with that.

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