1990 454SS tach
 

I have a 91 tach dash to put in my 1990 SS truck. I have done these before but lost the repin info. I have been all over web sites looking for that repin info but cannot find it. Anyone remember?
Thanks
Scott

Re: 1990 454SS tach
 

To use a 1991 cluster in a 1990 truck, you have to move B15 to B11, A11 to A10, and A10 to A9.

Re: 1990 454SS tach
 

Thank you very much. Which pin will serve the new lead from the tach?
Thanks Scott

Re: 1990 454SS tach
 

You're welcome!
B11
Signal to the tachometer.

Re: 1990 454SS tach
 

ChevyTech,
So your saying that the B15 connector that I'm going to move to B11 is a tach signal? I didn't think the 90 truck had an existing tach lead since it never had a tach?
Thanks
Scott

Re: 1990 454SS tach
 

That is what I have in my notes but I just looked at a 1990 C/K schematic and it shows that B15 is a ground wire and it shows no wiring for a tachometer.

I have never done this swap and my notes were from other members input from the boards.

If I can find some free time in the next few days I will do some research and post my findings here.

Re: 1990 454SS tach
 

B15 On a 1990 is a shared ground wire.
B15 on a 1991 is the wire in from the ignition for a tachometer.

At this point I don't trust any of the information because it is from other board members.

The way I see it, on a 1990 you need to run a new wire in from the coil to the instrument panel.

On a 1991 instrument panel B11 is the shared ground circuit 450. The shared ground circuit 450 is in position B15 on the 1990 instrument panel.

So to me it looks like the new tach wire from the ignition should go to B15 of the 1991 instrument panel when put in a 1990.

Re: 1990 454SS tach
 

Ok I looked at the schematics for the other wires and that information looks correct.

Move B15 to B11, Move A10 to A9, move A11 to A10

But then you have to run a wire in from the white tach lead at the ignition coil to terminal B15 of the instrument panel connector.

1991 looks to be the first year with wiring that includes a tach signal to the instrument panel.

Re: 1990 454SS tach
 

ChevyTech,
First of all thanks for hanging in there with me on this. Yes, on my 90 plug the B15 slot is a black ground wire. I have moved it to B11, that makes sense I believe. I will run a lead from the coil to B15 and hope the tach works. I will let you know tomorrow, I hope. Its awful hot in SW Florida now and working on the truck has become outside temperature sensitive. Thanks again. Scott

Re: 1990 454SS tach
 

You are welcome!
I will check back on this thread but am fairly confident it will work.

I understand the heat slowing you down. The only reason I am available on the board is I am worn out from the heat and resting where it is cool at my computer, and it is most likely much hotter where you are.

Re: 1990 454SS tach
 

I remember that there was an empty terminal wire right at the top of the coil. Used to be able to hook up a dwell tach to read the rpms working under the hood during tune-uos.

Re: 1990 454SS tach
 

Works great. B15 on the dash plug was the tach signal port. Extra wire coming off the coil to feed the tach was ea
sy. I hope this thread stays alive so that others can find it and easily do this task. Thanks for all the help.
Scott

Re: 1990 454SS tach
 

You're welcome!
Glad it worked out well for you.
Thanks for the update.
The thread should be around for people to find with a search.

Re: 1990 454SS tach
 

Thanks all for this info, I am looking to replace the cluster on my 90 and was wondering what needed to be done.

Re: 1990 454SS tach
 

You're welcome!
If you have any trouble doing your swap let us know.