Light bulb in Tach.

[JGrefenstette]

i have the isspro 4K rpm tach, and the bulb is just way too dim... Its a single 12v bulb that i think is about 3 watts??? anyhow, my question is, how high wattage can i put in there. ive found bulbs that will fit that are 12v all the way up to 75watts. i think a 5-35 watt is much more reasonable and is what i would probly like to use, but is there any problem with going to a higher watt bulb in the same socket with the same wiring... ??? thanks yall i just want to make sure im not going to melt out the back of my tach or fry my wires.

 

[DBF]

Lots of folks complain about the gage lights that ultimately are fed by the dashboard dimmer control. People like me with five gages are loading down things so every bulb, both gages and dashboard, is dim.

Many smart people here have shown us how to make the dashboard lights brighter (new bulbs, cleaning residue off current bulbs, etc. ). Done that, still dim.

Some day, some smart electrical guru will cobble together a module replacing the dimmer control, that raises the voltage (and thus, current) to the dashboard (and gage) lights, so the whole works gets brighter, all together.

Regards, DBF

 

[JLEONARD]

And I am just the opposite... I thought my Isspro tach light was too brite so I colored the bulb with a marker to make it dim. Mine was an easier problem to solve.

 

[PToombs]

Jimmy, I bet you can go to a 5 or 10 watt bulb and have no problems. Much more might be too much.

Just my nickels worth.

 

[JGrefenstette]

thanks pete. ill give it a try. and by too much do you mean, melt the gauge internals too much, or just too bright???



see guys, initially when i just had the tach and no other gauges, it was fine, a little dim but ok. once i put in the boost and egt tho, their sooooo bright it makes the tach almost not vissible, becuase your eyes adjust to the brighter ones and have a hard time picking up on the not so bright one under them. if you know what i mean.



im sure if i had the will power and time, i could find a way to gather all the insturment wires and run a line right of the battery and give them all a full 12-15 volts, by just bypassing the dimmer and running them through a seperate toggle switch. but their ok, for me, just need the tach a little brighter thats all.

 

[JGrefenstette]

the stock bulb is 3. 4watts. i just put in a 5watt. it seems to be just about right. i think a 10watt would be perfect, but the way the light projects through this style tach, im affraid it wouldnt look right. because the tach face is solid, and the light projects around its perimiter and through the center some. unlike my other gauges that the light shines through the clear or colored faces. so i may just have to be satisfied with the 5watt. but for now it really does seem a bit brighter than the 3. 4watt, so i very happy with it.

 

[sdstriper]

You are risking a meltdown in my opinion, the heat from those higher wattage bulbs is going to cook something. You might want to consider relays so your getting full voltage at the gauge bulb. If you have tapped into the dimmer circuit you know how tiny that wiring is, I would be surprised if you were at half the bulb rated voltage. Another option is LED bulb replacements, they draw a fraction of what incandescent bulbs do, less heat.

 

[JGrefenstette]

i was very close to doing the leds... . but.



realistically, the stock bulb was 3. 4 watts. how big a difference can a 5 watt make??? its only 1. 6 watt increase here. on a summer day where temps in the cab can be 100+ degrees not to mention the direct sunlight beating down on the gauge and the mount, how could 1. 6 watts be hotter than that, especially when im driving and the in-cab temps is more like 80 degrees.



dont get me wrong. if there really is a danger here of damaging my tach than ill go to the leds. ive already put in relays for the dimmer, that control the head lights and the tailights, so the dimmer has less load on it alread.

 

[PToombs]

Less load on the switch. The dimmer has more if the guages are tied into that circuit.

I was thinking of extra load on the switch too, that's why I recommended only a little larger bulb.

 

[JGrefenstette]

yea the gauges lights are, but that is all. as of now the only thing the dimmer switch has got on it, is my 3 guages, 2 front and 2 side marker lights, and the dash lights. so i think the elemination of the headlights and taillights leaves some room for the 3 little gauges dont you? what do you think pete, is the 5watt too much? and if so, for what, the gauge or the dimmer switch, or the wires?

 

[PToombs]

The only thing on the "dimmer" is the dash/guages! The marker lites run off a different section of the switch.

The 5 is most likely ok. Too big will burn up the wires and the switch.

 

[JGrefenstette]

thank you pete... . my fault. my ignorance shines through once again



im just gonna go for it. 5watts, a real splurge i know :-laf but ill take my chances, if it roasts, it roasts

 

[Moab4x4]

I did the LED route in the same guage. I converted all mine to LEDs to run cooler. Just look all those blue plastic covers inside the dash that are all deformed after a while. Stock 194's cook them babies. I took out the blue critters and installed red LED's. It took a little getting used to, but it makes all the red needles really show up. Red LED's in all dash lights and ISSPRO guages. (the green section of the EGT guage is a little hard to read, but who cares down there)



Downside, one brighness only, I don't have the load resistor in place to allow dimming. They just blink off when I get to the right spot on the dimmer knob. Resistor in series will fix that if I get too irritated.

Ken