Installing a tach

[pattison87]

Im installing a tach on my 87. I have all the wiring figured out for the power and for the tach to read correctly. The only thing i am having trouble on is what wire to splice into so the backlight of the tach turns on and dims with the rest of my dash lights. Any one have any ideas. Thank you.

 

[RetroC10Sport]

Go with the gray wire coming from the stereo. Or there's a spot on the fusebox.

 

[pattison87]

It has an aftermarket stereo. Someone told me to splice into one of the wires coming from the light/dimmer switch but never told me what color. Any ideas there?

 

[RetroC10Sport]

Gray wire. You could also use a connector and go to the fuse box, 6th cavity row over at the top is for illumination, above the INST LPS fuse. The row will be marked LPS.

 

[chengny]

Where do you intend to mount the tach? That might make it easier to help you find a convenient place to splice into the dimmed lighting circuit.

But it isn't that hard anyway. There are only 3 branches to that variable lighting circuit:

1. The illumination for the instrument panel
2. The radio back lighting
3. There is one bulb on the right hand end of the HVAC control panel

The last one - the heater control panel is probably the easiest to get to. But they all are on a common wire - the gray one that Retro mentioned.

But really, the easiest thing to do is just run the tachometer backlighting lead over to the fuse block (again, as Retro suggests) and plug into one of the sockets in the 2nd full column from the right. The column is labeled LPS:

 

[pattison87]

Thank you for your comments and help. Ill let you know how it goes