Relays
- Thread starter onlyav6
- Start date
DaveP's Ghost
Well-known member
That is not the OEM style relay, but it appears that it is plugged into the "Boost Control" relay connector. The boost control relay has 2 pnk/blk, 1 dk green, 1 orange wires. << This is how you confirm it that this is what it is. Wire colors. The empty relay connector in the pic is for the intercooler pump.
The relay is normally closed, IGN power (pnk/blk) on terminal 30 is passed through to the orange wire on terminal 87a. The orange wire is the (+) side of the waste-gate solenoid. The dk green wire goes to the lower heat exchanger probe. The idea was that if intercooler fluid level got low, the relay would open, and limit boost to 7psi base. The dk green wire also goes to the Low Turbo Coolant light in the instrument cluster.
To make these two things work requires a module that interprets the resistance at the probe, and if out of range by "low coolant", the module grounds the green wire to energize the relay which removes the (+) to the waste-gate solenoid and turn on the light. Well, somehow or another this module was never incorporated into the trucks when built. So as-delivered, neither the relay or the light function, and never did.
In 2000, I wrote an article describing how to wire the module to make these things functional. It was in The Vault, which was not reinstated when Keith updated the site. I had the part numbers for the module and pigtail from a C4 Corvette which worked well in the SyTy. I converted two of my trucks, and one is still in my yard, and the light works. No way are the parts to convert it still available, nor is it a big deal that they don't work. If you still have a waste-gate solenoid, with the key ON, check that there is 12 V at the orange wire at the solenoid. If = YES, that's all you need to do.
I know, TL;DR. But now you know the full story. Not many of us that were figuring this stuff out 20+ years ago are still around. Not too far into the future, these tid-bits will be lost forever.
The relay is normally closed, IGN power (pnk/blk) on terminal 30 is passed through to the orange wire on terminal 87a. The orange wire is the (+) side of the waste-gate solenoid. The dk green wire goes to the lower heat exchanger probe. The idea was that if intercooler fluid level got low, the relay would open, and limit boost to 7psi base. The dk green wire also goes to the Low Turbo Coolant light in the instrument cluster.
To make these two things work requires a module that interprets the resistance at the probe, and if out of range by "low coolant", the module grounds the green wire to energize the relay which removes the (+) to the waste-gate solenoid and turn on the light. Well, somehow or another this module was never incorporated into the trucks when built. So as-delivered, neither the relay or the light function, and never did.
In 2000, I wrote an article describing how to wire the module to make these things functional. It was in The Vault, which was not reinstated when Keith updated the site. I had the part numbers for the module and pigtail from a C4 Corvette which worked well in the SyTy. I converted two of my trucks, and one is still in my yard, and the light works. No way are the parts to convert it still available, nor is it a big deal that they don't work. If you still have a waste-gate solenoid, with the key ON, check that there is 12 V at the orange wire at the solenoid. If = YES, that's all you need to do.
I know, TL;DR. But now you know the full story. Not many of us that were figuring this stuff out 20+ years ago are still around. Not too far into the future, these tid-bits will be lost forever.
RealFastV6
@jb_and_his_coffee
Here ya go Dave...