tachmeter bulb replacement

[kully 560]

I am trying to change the bulbs on the speedo meter and the tach meter and I have a dash cover, so I can't remove the guage. but I removed the center dash where the flip down light is and removed the heater flex hose. and now can reach the sockets but do they just pull out or twist out? thanks

[Racer X]

The bulb sockets should just pull out, but twisting them a bit may help them come out.

[kully 560]

thanks I did get them out but when I changed to led they will not light because of the low power draw . any why to bypass the dimmer?

[Racer X]

1 hour ago, kully 560 said:

thanks I did get them out but when I changed to led they will not light because of the low power draw . any why to bypass the dimmer?

This guy built a digital dimmer.

https://woodworkerb.com/home/datsun-240z-rebuild/changing-instrument-lighting/

[Zed Head]

1 hour ago, kully 560 said:

thanks I did get them out but when I changed to led they will not light because of the low power draw . any why to bypass the dimmer?

Not really sure what you're saying here.  There is no flasher on the tachometer bulb circuit that needs current to work properly.  Id' guess that you have a contact problem.

[cgsheen1]

1 hour ago, kully 560 said:

thanks I did get them out but when I changed to led they will not light because of the low power draw . any why to bypass the dimmer?

Gauge lighting, correct? I didn't have any problems swapping my incandescent bulbs for LED bulbs and they dim with my stock rheostat. (I also replaced the turn signal and high beam indicators without issue) I used these: 

Amazon.com: QasimLed Bayonet BA9 BA9S 53 57 1895 64111 T4W Super Stable and Bright Led Bulbs Exterior Marker Indicator Interior Reverse Side Corner Light White 12V DC 10pcs : Everything Else

 

[SteveJ]

2 hours ago, kully 560 said:

thanks I did get them out but when I changed to led they will not light because of the low power draw . any why to bypass the dimmer?

Did you test them with the bulb socket re-installed? The ground for the 240Z gauges is the gauge body.

Another problem could be some LED bulbs are positive ground. I found that issue early on when I started experimenting with LED bulbs.

Just make sure the dimmer is turned all of the way up. However, LED bulbs tend to be less voltage sensitive than incandescent bulbs.

Edited September 24, 2022 by SteveJ

[kully 560]

the 260z sockets have its own ground wire. I changed the 3 smaller gauges with no problem to led bulbs. and no problem with them working and dimming. I managed to remove the tach sockets from under the dash and when I installed the first led, it was working but when I installed the second led bulb nothing. I did have only 1 bulb working in the speedo as the bottom bulb was not working.  I did try to bypass the dimmer with a jumper and nothing. but I did manage to change the bad bulb in the speedo that was not working but I went back to the 4w bulb. I would have thought with the low power draw from the leds that bypassing the dimmer would have worked. thanks for the help so far.

[kully 560]

thanks zed head, I know there is no flasher. if there was one, they would most likely just stay on all the time and not blink. I did get down to 2 -3w bulbs left and changed 1 of the 2 to the led type and then the dash lights went out! so I installed the old bulb in the same socket and bingo they all came back on!

[SteveJ]

1 hour ago, kully 560 said:

the 260z sockets have its own ground wire. I changed the 3 smaller gauges with no problem to led bulbs. and no problem with them working and dimming. I managed to remove the tach sockets from under the dash and when I installed the first led, it was working but when I installed the second led bulb nothing. I did have only 1 bulb working in the speedo as the bottom bulb was not working.  I did try to bypass the dimmer with a jumper and nothing. but I did manage to change the bad bulb in the speedo that was not working but I went back to the 4w bulb. I would have thought with the low power draw from the leds that bypassing the dimmer would have worked. thanks for the help so far.

If the second bulb was in the speedometer, that was the problem. Incandescent bulbs don't care about polarity. When I was going to LEDs in my gauges, I ended up replacing the sockets to wedge sockets. That allowed me to flip the bulbs around if the polarity wasn't right.  I didn't try to prove it out, but I think one of the bulbs in the speedometer is wired backwards. That is what provides the challenge of swapping to LEDs. Once the one diode blocks the current flow, none of the bulbs will light up.

[kully 560]

hi Steve, I did some research and read you reviews on the led bulb, and I did order the same ones that you used from amazon the green duabhoi brand. and I did not find them polarity sensitive. 

[SteveJ]

1 hour ago, kully 560 said:

hi Steve, I did some research and read you reviews on the led bulb, and I did order the same ones that you used from amazon the green duabhoi brand. and I did not find them polarity sensitive. 

I was looking through my past orders. Duabhoi bulbs were 1156. The dash bulbs I used in the 240Z were Yongming.  I don't recall if I tested them for polarity sensitivity. I do recall having the issues with the bulbs back 8 years or so ago for the gauge lights in the 260Z hence my unorthodox solution. I also recall a friend having issues with converting a 280Z over to LED bulbs for the gauges a couple of years ago. I can't recall if he found a solution.