SPA Gauge as a Cool Down Timer

[Matt400]

Rumor has it that someone's done it.



The SPA can drive a relay at any user selected temp but I can't visualize the schematic on how that would work because the gauge is powered by a keyed power source so turning the key off kills the gauge.



Powering the gauge direct would have it on even after shut down.

How do you keep the gauge powered up with the key off and yet shut the gauge off after it kills the engine?



Anybody done it?

 

[Matt400]

Hrmmm... I am thinking a pair of relays, Relay #1 to take over power supply to the gauge and continue ignition after the key is shut off then Relay #2 to shut down the ignition and gauge once the temperature is met.



Anyone like to comment on how their aftermarket cool-down timer connected??

 

[TxDieselKid]

If you search for this topic, look for posts from HVAC. Some of his friends were the ones that came up with it, and did it first. He explained it on here in a post from about 2+years ago.

 

[Matt400]

Thanks for the tip... I couldn't find anything but enjoyed reading HVAC's posts.

I did talk with Brandon about this and he remembered someone had done it and was going to check into it for me, I will meet up with him on Thursday.

 

[TxDieselKid]

Brandon is a great guy taht will never lead you down the wrong path.

 

[Matt400]

Well Brandon was kind enough to supply me with a circuit he felt should do the trick, not sure where he got it from and no directions so I kinda reversed enginered the piece to see what/how it could work.



I got around to testing it today and it works. So yes it is possible to use your SPA EGT gauge as a turbo cool down devise. Not a timer because it shuts the truck off at what ever temp you set the SPA's external alarm at.



You can pull out the key and lock the doors with the fob just fine. This is on the 03 anyway.



Now I just need help from someone that can teach me how to draw up a wire diagram.

I can do it with a pen but don't know how on the PC. If its a big deal to learn maybe someone will let me fax them a pen drawing and they can do on a PC and post it here.

I am willing to learn... anyone??



The only parts needed is this relay:

http://relays.tycoelectronics.com/datasheets/OUDH.pdf

A diode, some wire and a 10A fuse.



On my final install I will splice in a toggle so I can shut the truck off right away if needed or flip it off to disable the system for the wife that may wig out while shopping.

I have given her a heads up though and she just rolls her eyes