Testing MSD Window Switch
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 7,032
Likes: 2
From: Newburgh NY
Testing MSD Window Switch
If I run a ground directly to the activation relay and engage the WOT everything works great. However, if I connect the ground through the MSD Window Switch then the solenoids do not kick. Obviously something is wrong.
I have the white tach wire from the MSD Switch going to the White wire on the blue side of the PCM (it's a 98). I did not see any other "white" wires in the harness going to the blue side and it looked to come in around pin #35.
I have the red wire from the MSD going to a +12 switched
I have the black going to a ground location under the dash that I tested and have other ground going to.
I have the yellow going to the relay's ground.
To me this means that when between 3k and 6.2k (those are the pills I currently have installed) the MSD should complete the ground loop to the relay, but doesn't.
Is there a way to check to check the MSD (Hook up a separate tach to it somehow). I tried pulling the pills thinking that would create a loop that I could test with but that also did not work.
Any suggestions?
Thanks
I have the white tach wire from the MSD Switch going to the White wire on the blue side of the PCM (it's a 98). I did not see any other "white" wires in the harness going to the blue side and it looked to come in around pin #35.
I have the red wire from the MSD going to a +12 switched
I have the black going to a ground location under the dash that I tested and have other ground going to.
I have the yellow going to the relay's ground.
To me this means that when between 3k and 6.2k (those are the pills I currently have installed) the MSD should complete the ground loop to the relay, but doesn't.
Is there a way to check to check the MSD (Hook up a separate tach to it somehow). I tried pulling the pills thinking that would create a loop that I could test with but that also did not work.
Any suggestions?
Thanks
Melting Slicks
Joined: Mar 2003
Posts: 3,116
Likes: 10
From: Macomb MI
Re: Testing MSD Window Switch (78Vette-SA)
Do you have it setup in 4 cylinder mode? It must be set this way
You can also use a simple test light hooked to power to test the lead to the relay.
If its a switched ground output, hook the lead of the test light to +12v and the probe to the msd output and test. If the light lights at specified rpm then circuit is working.
Phil
You can also use a simple test light hooked to power to test the lead to the relay.
If its a switched ground output, hook the lead of the test light to +12v and the probe to the msd output and test. If the light lights at specified rpm then circuit is working.
Phil
