bparker

I have a thread about wanting to lockup my TC and it dawned on me that "Hey - MSD makes a Window Switch that "could" do this too". :confused:

Can you adapt a MSD Window Switch to - send a lockup command (adjustable) during certian RPM Ranges and only at WOT during certian gears?

I think this would be the MOD of the year IMO. :yesnod:

Thanks for your help,

BP

Austrian Vette

On WOT you will want to have the TC locked up only in third gear and not
i different gears. Or you will kill the TC or/and the tranny.
I really would do that switch!!

BUT, yes, it would work, you only would want to do it over a relay as the ground output of the MSD windowswitch is not strong enough.

Again, I recommend to do a switch and only lock the TC in 3rd gear.

Michael
Michael

bparker

OK - so via the window switch, you can use it to lockup the converter in 3rd? Humm - good idea or bad? :confused:

Austrian Vette

How does the Window switch know that you´re in third!!!
He only sees rpm and then gives the signal.
The window switch doesn´t see if you´re in 1st, 2nd,......

So I would say, ...bad idea.

You don´t want that toggle switch, do you :D

Michael

bparker

HAHA - :lol: yea - I am lazy I guess - or I know I will always think that I hit it late or something .. hehe

I dont know much about window switches, as I do not use NOS - thus I assumed that they would/could track what gear you are in too..

Humm - I guess I have beat this bush enough to grab a toggle switch and some wire.. :smash:

Thanks so much for your help and ideas..

vette.se

bparker,

It could be possible to do what you want. I looked in a -98 Service manual where you have a description about the electronics controlling the Automatic transmission. Pin 40 with a Yel/Blk wire at the PCM controls the 2-3 shift solenoid. This pin is grounded when doing the shift but I do not know if its grounded for a very short period of time just doing the shift or if its grounded until next shift.

I would suggest what you hook up a multimeter measuring the voltage at this pin and do a test drive. If its grounded as long as you are in third gear you only have to hook up a relay to + 12V and to the PCM #40 Yel/Blk wire. If it's only a pulse(Hopefully it's long enough to be seen on the multimeter) you have a little more work to do, in this case you would need to build some electronics or get a impulse relay with reset possibilities. If it is a pulse you need to connect the PCM #40 Yel/Blk wire and the PCM #34 WHT to the electronics using the #40 as a 'Set' and the #34 as 'Reset'. The #34 is the 3-2 down shift solenoid. I assume you want a RPM window switch to have this happen at certain RPM's as well and to make sure nothing goes wrong you should use the RPM switch to keep the electronics or pulse relay in a 'Reset' state until the RPM are within the window you setup.

Please hook up a lamp or something and do some test drives BEFORE you connect the lockup to avoid any mishappenings ;)



[Modified by seanr, 10:54 AM 11/11/2001]

rwj383

the window switch can be used to switch anything you want. BUT, you have to remember that the MSD output is only 1.5A. i would suggest switching on/off the coil of another 12vdc auto relay with this (as i have done in my nitrous system). the output of the MSD would go to one leg of the relay coil, the other leg of the coil to ground. then you can route anything you want through the contacts of the relay, up to the limitations as advertised, to complete the path for your TC signal.