GM 5.3L DBW Cruise Control Help (1 Viewer)

[Krazytoy]

I have a 1986 Toyota Land Cruiser that the previous owner swapped in a 2004 DBW 5.3 and 4l60E mated to the stock Toyota transfer case. I am in the process of hooking up the CC and have read several threads that have directed me, this one in particular http://www.lt1swap.com/dbw.htm.
The issue that I am having is the factory Toyota brake switch has to run to a relay to reverse its operation for the torque converter unlock. I hooked all the wires up last night and I taped into the hot wire from the brake pedal into the relay, now when I hit the brakes the brake lights stay on, the stock LC brake switch only has 2 wires that go into it, a hot wire in and the wire out that is energized when the brake pedal is applied. I have read that the cruise will not function unless the PCM sees resistance from the brake lights. Is there a way I can get power to the CHMSL with this set up?

 

[Dynosoar]

Swap in a GM switch it is almost a direct swap. The hole for the shaft will need to be opened up just a bit.
Dyno

 

[Krazytoy]

Swap in a GM switch it is almost a direct swap. The hole for the shaft will need to be opened up just a bit.
Dyno

What switch are you talking about? The column switch or the brake switch? If I swapped in the brake switch then I would still need a relay to reverse the switch to make the brake lights work. Column switch would not fix the problem either.

 

[MarkN]

the relay will work, that's what I did on my Land Cruiser 5.3 swap. GM makes a brake switch that has both a normally open and normally closed function. I used this on my 69 K10 5.3 swap. The GM switch is less complex and more than likely more reliable than using a relay.

Can you post a sketch of what you have done?

 

[MarkN]

See if this will help..

 

[MarkN]

Here is the switch Dyno was speaking of..

 

[dbleon]

The 4 prong GM switch is exactly what I used... Avail at the local auto parts store. I have yet to hook up cruise on the DBW... its is on the very short list, along with backup lights etc.

 

[Krazytoy]

I figured it out! Since I was pulling the pin 6 wire to the TAC from the relay it did not have any resistance, the pin 6 MUST have at least 6 Ohms of resistance (same as a 1157 bulb). I wired a 1157 bulb in line with the pin 6 wire and it works perfectly!

 

[Krazytoy]

Markn, that diagram will not work, I had it wired that way and it would make the break lights stay on permanently.

 

[MarkN]

Markn, that diagram will not work, I had it wired that way and it would make the break lights stay on permanently.

It works on mine.. must be some difference between the vehicles...

 

[MarkN]

I figured it out! Since I was pulling the pin 6 wire to the TAC from the relay it did not have any resistance, the pin 6 MUST have at least 6 Ohms of resistance (same as a 1157 bulb). I wired a 1157 bulb in line with the pin 6 wire and it works perfectly!

The Tac pin 6 should have came off of the brake switch and not the relay..

 

[Krazytoy]

The Tac pin 6 should have came off of the brake switch and not the relay..

Again, I had it wired that way and when you applied the brakes the brake lights would stay on permanently.

Main point is the TAC pin 6 has to see resistance for the cruise to work.

 

[papagyo]

dbleon,

Just have to ask, are you saying that if you swap out the toyota brake switch with the GM one you can eliminate the relay used by most during a 5.3(4L60E) swap? The wire that unlocks the TC when brake is applied? Thanks.

Brian

 

[dbleon]

That is how mine is done. Might depend on harness. I run an uncut gm harness. I forget the exact wiring but it works...no relay.

 

[MarkN]

Again, I had it wired that way and when you applied the brakes the brake lights would stay on permanently.

Main point is the TAC pin 6 has to see resistance for the cruise to work.

cool..

 

[MarkN]

dbleon,

Just have to ask, are you saying that if you swap out the toyota brake switch with the GM one you can eliminate the relay used by most during a 5.3(4L60E) swap? The wire that unlocks the TC when brake is applied? Thanks.

Brian

Yes... the normally open part of the switch would go to your brake lights and to the P6 of the TAC for the cruise. The normally closed part would be used for the TCC lockup..

A relay works as well... but the switch should be less complex and more reliable.

 

[Krazytoy]

Definetly agree that the switch is less complex, I ordered one today for about $20 to my door. The reason I was just trying to make it work is because the PO told me he "tried" to make it work but thought there may be an issue with the vss. Now that I know it works I'll clean it all up.

 

[FJ60Cam]

This may be a dumb question, but how are you guys enlarging the factory brake switch hole to accept the GM switch?

I don't see how to fit any tools in there without taking a lot of stuff apart.

 

[MANUCHAO]

Dremel tool..

 

[FJ60Cam]

Awesome, thanks!