I have searched the f.a.q's.I want to swap my dash with no gauges on my 87 firebird for a cluster with gauges and elecrtic speedo.The guy is willing to include a sending unit from trans but not that car?.Will the swap work if i use everything from the donor car,mainly the dash wire harness.It looks like the conections are the same .The complete dash harness from bulkkhead to e.c.m

 

I think the gage pods are interchangeable from '86 to '92 as long as your car is same year or newer than than the donor car. Not sure it is backwards compatible in all cases because at some point they stopped placing the alternator excitation resistor in the circuit board.

 

Ok thanks.My car is older than the donor car.I was hoping to install a factory gauge cluster to get the factory electric speedometer to work with my cruise control.I tried a cluster before with the off site speedo swap and it worked,but my cruise wouldn't work because the site explaining the buffer wires doesnt show how to hook up the the 2 wires for cruise.

 

You just need to study a few wiring diagrams. You're cable drive speedometer should have an optical VSS on the back of the cluster. An electric speedo firebird pre-1990 should have a VSS buffer box mounted by the ECM to convert the signal from the 4000ppm the Speedometer requires and the VSS generates to the 2000ppm the ECM and the cruise control uses. So in short, if you can make the speedometer work, you just need to add in the VSS buffer to convert the signal for the computer and/or cruise control.

 

Yes,my cable driven speedometer does have a little yellow box on the back of the cluster .I noticed it even has the same color wires going into it that an electric speedometer has.I not sure what year car the buffer I have came from.I have a factory service manual I been looking at but I cant tell for sure where the 2 wires not listed on the offsite speedometer swap picture of the buffer go to.On that site,the wires not used are listed as brown.Mine are 1 brown and 1 solid red .I am affraid if I get something wrong I will damage my e.c.m.The site I am referring to is connected to this site.I will try harder to figure it out.Thanks for the reply

 

According to a the 91 Firebird service manual, looking up the buffer on a TBI 305... Brown is 2000ppm out to the ECM, Red is 2000ppm out to the cruise control module.

 

Thanks for your help.I am going to use my service manual to see where these imputs are and tie into them.

 

I'm doing the swap on my 84 Firebird right now it IS NOT a plug and play you have to move the wiring into different spots on the plugs on the back of the cluster they are different from cable drive speedo and electric speedo so you also have to ADD a wire for the speedo.

Also if its the Firebird you have VERY short wires to work with they are only about two to three inches to work with without cutting up the dash.

I recommend you to go to your nearest library and get a manual one for the older car and one for newer dash with wiring diagrams and compare the two wiring diagrams.

There is a guy on this site somewhere I'm not sure where who has the complete break down of it if you can find him.

 

I got all the info,some from this sight,and the rest from my Service manual.I got everything wired up and installed.The volt gauge read low,oil pressure gauge pegged,and tach was off.As it turned out,I had to pull cluster and reuse my old 1 because I was told that G.M didn't make an electric speedometer sending unit for the t-5 transmissions until late '80s cars and my t-5 came from '85 Firebird.The tailshaft is different in later cars,so I was told by people at HAWKS.They said my only option was to buy a box they sell for $300.00 to convert to electric and I cant pay that.So now I have a GTA 140mph cluster collecting dust on a shelf

 

That's not entirely accurate. The tailshaft of the trans is the same, problem is the electronic speedometer sender is discontinued, and hasn't been available in years.

 

Ok.I didn't know that.When I called HAWKS,I thought they could get me a used one.I will just have to search the web and keep my eyes open for one.Thanks Drew.