DBW Cruise: Dummy Tail Light
03-07-2011, 05:09 PM
#1
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DBW Cruise: Dummy Tail Light Trying to get the cruise control to work on my DBW LSX. Is this the correct way to wire in a resistor to act as a dummy stoplight so the PCM sees the correct current flow?
Thanks for the help.
Thanks for the help.
03-07-2011, 07:33 PM
#2
BTW, I don't know if you found a source for a resistor yet, but if you haven't, check out mouser.com - they're an electronics supply house. I think this application requires something like a 6 ohm resistor. I am going to get one with a pretty high watt rating - probably somewhere between 3 and 5 watts (as compared with the 1/4 watt resistors you find at Radio Shack.) I think the higher wattage resistor will take on more current (and heat) for a longer time without failing.
If you go to mouser.com, check out Passive Components / Resistors / Metal Oxide Resistors
It'll probably run you about 50 cents plus $6 S/H.
Last edited by FastKat; 03-07-2011 at 08:00 PM.
03-08-2011, 09:05 PM
#4
Hey Phil! No, my Jag is not yet on the road. I am having a hard time finding time to work on it, especially with it being 200 miles away. Hopefully this summer...
I just checked the cruise and exterior lighting diagrams for a 2004 Corvette (which still uses a TAC module) and that is how it is wired. Instead of using a resistor, they used the third brake light.
Just to be clear, "+12V w/brakes on" is the brake switch, "light blue to 'stop light'" runs to the TAC module, and of course "ground" is ground.
I just checked the cruise and exterior lighting diagrams for a 2004 Corvette (which still uses a TAC module) and that is how it is wired. Instead of using a resistor, they used the third brake light.
Just to be clear, "+12V w/brakes on" is the brake switch, "light blue to 'stop light'" runs to the TAC module, and of course "ground" is ground.
Last edited by FastKat; 03-08-2011 at 09:11 PM.
03-09-2011, 08:58 AM
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Mine's emissioned and licensed but it quit on me backing out of the driveway about a month ago.
When I modified the shift linkage on the trans to work with the Jag's gear selector, the Jag's shift cable rubbed the wires going to the gear selector connector and shorted one of them out.
I pulled the harness out of the car to modify it and thought I'd hook up the cruise control. I didn't want to go in and tap the brake light wire on the Jag, so I ran a relay off the wire that signals the torque converter to lock up. The logic is that there is 12V off the relay either going to the TCC or to the dummy brake light. I'll send you a schematic if you think it might be useful on your project (after I make sure it works tonight)
With gas prices escalating so rapidly, I'd like to see what the Jag will do with the cruise control working properly.
Work is picking up here too and car project time is getting scarce, but perhaps that's a good thing.
Phil
When I modified the shift linkage on the trans to work with the Jag's gear selector, the Jag's shift cable rubbed the wires going to the gear selector connector and shorted one of them out.
I pulled the harness out of the car to modify it and thought I'd hook up the cruise control. I didn't want to go in and tap the brake light wire on the Jag, so I ran a relay off the wire that signals the torque converter to lock up. The logic is that there is 12V off the relay either going to the TCC or to the dummy brake light. I'll send you a schematic if you think it might be useful on your project (after I make sure it works tonight)
With gas prices escalating so rapidly, I'd like to see what the Jag will do with the cruise control working properly.
Work is picking up here too and car project time is getting scarce, but perhaps that's a good thing.
Phil
Hey Phil! No, my Jag is not yet on the road. I am having a hard time finding time to work on it, especially with it being 200 miles away. Hopefully this summer...
I just checked the cruise and exterior lighting diagrams for a 2004 Corvette (which still uses a TAC module) and that is how it is wired. Instead of using a resistor, they used the third brake light.
Just to be clear, "+12V w/brakes on" is the brake switch, "light blue to 'stop light'" runs to the TAC module, and of course "ground" is ground.
I just checked the cruise and exterior lighting diagrams for a 2004 Corvette (which still uses a TAC module) and that is how it is wired. Instead of using a resistor, they used the third brake light.
Just to be clear, "+12V w/brakes on" is the brake switch, "light blue to 'stop light'" runs to the TAC module, and of course "ground" is ground.
03-09-2011, 09:57 AM
#6
Glad to hear it's on the road and through all the administrative stuff! Did you have to go over some parts in the rear suspension cage, too?
What you're describing is similar to what I did on my car. Instead of using the brake light switch/circuit, I used the "brake operated switch" which is part of the Jag cruise control system. It is a normally closed switch mounted at the top left side of the brake pedal. I use that switch to control a relay that operates both the torque converter lockup signal and the cruise control brake signal.
I ordered a few 3W and 5W resistors (for my oil pressure gauge, cruise control wiring, and alternator), some loose connectors, and an OBD/CAN diagnostic port with mount holes (only $.88!) from Mouser.
What you're describing is similar to what I did on my car. Instead of using the brake light switch/circuit, I used the "brake operated switch" which is part of the Jag cruise control system. It is a normally closed switch mounted at the top left side of the brake pedal. I use that switch to control a relay that operates both the torque converter lockup signal and the cruise control brake signal.
I ordered a few 3W and 5W resistors (for my oil pressure gauge, cruise control wiring, and alternator), some loose connectors, and an OBD/CAN diagnostic port with mount holes (only $.88!) from Mouser.
Mine's emissioned and licensed but it quit on me backing out of the driveway about a month ago.
When I modified the shift linkage on the trans to work with the Jag's gear selector, the Jag's shift cable rubbed the wires going to the gear selector connector and shorted one of them out.
I pulled the harness out of the car to modify it and thought I'd hook up the cruise control. I didn't want to go in and tap the brake light wire on the Jag, so I ran a relay off the wire that signals the torque converter to lock up. The logic is that there is 12V off the relay either going to the TCC or to the dummy brake light. I'll send you a schematic if you think it might be useful on your project (after I make sure it works tonight)
When I modified the shift linkage on the trans to work with the Jag's gear selector, the Jag's shift cable rubbed the wires going to the gear selector connector and shorted one of them out.
I pulled the harness out of the car to modify it and thought I'd hook up the cruise control. I didn't want to go in and tap the brake light wire on the Jag, so I ran a relay off the wire that signals the torque converter to lock up. The logic is that there is 12V off the relay either going to the TCC or to the dummy brake light. I'll send you a schematic if you think it might be useful on your project (after I make sure it works tonight)
