Any circuit genius' here

[modular93fox]

Well I finaly got my tow/haul feature working on my 5.3 swap in my 87. Factory 5.3 silverados have a momentary push button at the end of the shift lever, 73-87 silverados dont, never offered and probally won't find anything that will either look right or fit.

while typing something I found an awesome solution, but the internets doesnt have an "easy button".

Ive got the cruise control working and the factory stalk switch has a button ("set") on the end that could be the momentary ground switch I need to activate the tow/haul. What I want to do is have a simple circuit, probally uses a transistor to make it simple and small.
Idea:
When the on/off switch is "off", the transistor will allow the factory cruise control "set" button will be the tow/haul switch.
When the on/off switch is "on", the tow/haul feature will no longer be available, trans setting normal or tow/haul will either depending on if the button was pressed or not, but the "set" button will be used for the cruise control circuit only.
The schematics I've found make it look simple, but they use calculations that make my head hurt. I can see the transistor as a simple relay.... but just dont have the know how. Anyone here a circuit genius?
Thanks,
clint

[modular93fox]

Think I might have found a simple way of doing it use a mini relay.
Pin 85 -ground
Pin 86- cruise on (12v on, 0v off)
Pin 30- ground
pin 87a - cruise control "set" button
pin 87 - tow/haul

it should work. Im not sure which 87 or 87a is normally closed with no power supplied to the relay, that will be the tow/haul, only when the cruise is used will the relay be energized.
clint

[esenior]

87a is normally closed. So if you want the button to control cruise set, then you would want to attach the cruise set to 87 and the tow/haul to 87a. That way, when cruise is off, no power is applied and the button is passed through to pin 87a (tow/haul)

Some pretty good relay diagrams and information available at the 12Volt.com (http://www.the12volt.com/relays/relays.asp)

[parsonsj]

Seconded on the The 12Volt.com website! Great stuff over there.

jp

[modular93fox]

yeah, im going to have to re think it again. the cruise control has 12v inputs to the cruise module, so no go on the first idea... i need to figure out how to make an electircal train track switch :)....im off to 12volt.com
thanks,
clint

[modular93fox]

ah, a DPDT relay should do the trick... now i just need one :)