hey guys i jst recently swaped in a carbed 350 in place of my 305tbi and i tore out the whole harness and rewired a bunch of things. almost all things i wired needed 12v key on so i stuck them into open spots on the fuse panel with flat male connectors. now my speedometer was one of the things i had to wire up for 12v. and if i have my stereo on with my subs and i hit the gas the speedometer drops to 0 then goes back up when i take my foot off the gas. so i am thinkin i have to many things running into my fuse panel and i need to do this the proper way. now is there a better way to go about wireing things up like this? i was thinkin getting one of them blocks were u put one power and one ground and u can hook up multiple things to it. thanks guys

 

OOOOOOOOOOHHHHHHHHHHHhhhhhhh man you have to help me. my spedo doesnt work anymore after i did my TPI -> carb conversion. i have an 89 trans am GTA. everything works nicely EXEPT the freaking spedometer. everyone i talk to keeps saying theres a cable going directly to it that runs it, and it shouldnt be electrical. thats total i spent an hour under my car looking for this magical "cable" that everyone is talking about and it just simply doesnt exist. there is only one thing i can see that "could" be the spedometer "wire" and thats the little plug thingy near the back of the tranny going into this little modual type thing. its got 2 purple wires 1 yellow wire and a green wire(not sure about the green one). i tryed following them and most of them go inside the dash. after that, im lost. there is a big nasty pile of wires under my dash and i reaaaaly dont feel like pulling my whole dash appart to find 1 or 2 wires. also, my heater fan doesnt work anymore, did yours work after you ripped out the ecm?

 

Shoudn't have ripped out the stock harness huh! My car is carbed and I still have the stock harness in it.

 

yeah well... i want my engine bay to look clean and simple. i dont like it being all crowded with useless wires that can catch on fire or melt due to a power wire grounding on the frame... come on, help me out here, ill be your best friend

 

Well see i tore out my harness cause if i am not going to need it then why would i have it? and plus i like to do things right. Ok about your speedometer, under your passenger side panel above where your feet go there is a yellow box and u have to supply 12v to one of the wires comming out of the box. i do not rememer for sure but i am thinkin maybe purple?well u can just test that and figure it out. If u have a hard time let me know and i will go check for you. good luck bud.

 

Psyte,

There is no speedometer Bowden cable on your car as in older cars. Your transmission is equipped with a VSS, which encodes vehicle speed to send to the ECM and speedometer head. Look under your car and see if you have one of these:

 

um... the thing is... its not here, its at an autobody shop. i should be getting it back soon, but this is something that needs to be done when i get it back. im pretty sure its got something that "looks" like that near the back of the transmission. is there anything other then that i could possibly have? i swear there is no cable. its an 89 trans am GTA 5.7L . is it most likely this car would be equiped with it? wich wire do i attach to the spedometer wire (if one exists?) or do i need a new speedometer now that my ecm isnt there? 89formula, that little yellow box... are you sure all i have to do is supply power to one of those wires? ill give it a shot anyway, but couldnt this fry something if i get the wrong one?