I have a customer who wants me to install a DSP2 tune into his 04 LLY, this is not my question. The question/issue comes in when he states that he would like the DSP tune to activate when he activates the tow/haul mode on his truck. What I'm wondering, is can anyone who has access to GM specs, or has knowledge about the BCM tell me if the circuit for the tow/haul indicator light would handle the load of the lamp in dash and a small relay to make this possible? He doesn't want ANY additional switches inside his cab, this is the issue, LOL! :baby:
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- Thread starter Mike_S
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I cant say whether the BCM does or not but I would not tap into the indicator light for your signal.. What is the big deal with a switch? Race cars have switches and race cars are cool
IIRC:
The DSP2 switch is just a ground detect switch. No real current goes through it.
But getting to the T/H light is normally done by removing the speedo cluster and soldering to the back of the light. Not sure if you can work it by using the switch wire, since the switch wire is also just a ground detect for the TCM.
The DSP2 switch is just a ground detect switch. No real current goes through it.
But getting to the T/H light is normally done by removing the speedo cluster and soldering to the back of the light. Not sure if you can work it by using the switch wire, since the switch wire is also just a ground detect for the TCM.
I cant say whether the BCM does or not but I would not tap into the indicator light for your signal.. What is the big deal with a switch? Race cars have switches and race cars are cool
LOL! While I agree that race cars with lotsa switches are cool, I can also see where he is coming from with this "stealth" aproach. :rofl:
If it were me , I would try it on my own truck first so the customer's truck wasn't at risk, but doubt it would be an issue , it only takes .30 amps to fire a standard 30 amp 5pin relay coil I doubt it would be an issue , just use the signal to ground side switch the coil on the relay and use the load side of the relay to trigger the ECM and it would also "isolate" the circuits .
I would use a relay like this. http://cgi.ebay.com/10-X-Mini-Power...ultDomain_0&hash=item1c197dd7f2#ht_1901wt_689 Smaller coil so less load. If you really wanted to be trick you could build a latch so it cycled on tow/ haul, and stayed that position untill it went back to towhaul. I'm sure there's an indicator somewhere in a stock location you could use to be able to tell.
Edit forgot the link:banghead:
Edit forgot the link:banghead:
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Certainly not an electronics guy, it seems what you want is actually a transistor, not a relay. Transistors trip with almost no current at all. 300 milliamps (.3a) is actually a lot of current for electronic circuits, and can burn out most circuit boards.
You will put a resistor on each side of the transistor, one between the LED and the signal wire, and one between the ground wire and the car ground.
Someone who is smart should pipe up though.
You will put a resistor on each side of the transistor, one between the LED and the signal wire, and one between the ground wire and the car ground.
Someone who is smart should pipe up though.
We kinda lose the stealth approach when smoke starts rolling? An put some guages like I did withe the switch there?
his truck smokes very very little as per his request. Just trying to figure this out for him. It would be cool for some people to have it this way.
The BCM has no outputs for T/H whatsoever. T/H is activated via a Class2 signal from the BCM. Teh T/H indicator is also activated via a Class2 signal. The only option would be to tap into the cluster's light.
That's how the ATS CoPilot (gen 1) got it's T/H signal, was soldering a wire onto the back of the instrument cluster.
This was my plan, what I'm trying to discover is how tough the driver circuit for that light is. If I have to figure out a solid state relay (so to speak) then so be it, but if I can drive a very small relay off if that circuit it will save me some work and simplify things greatly.