instrument cluster bulb question
03-10-2014, 07:18 PM
#1
Rennlist Member
Thread Starter
instrument cluster bulb question
while i am waiting on my defroster vents, I am doing the led conversion on my instrument and replacing the burnt out D gear selector light.
my question is that on later model clusters you can get an entire socket assembly with the LED built in.
I want to go this route instead of buying the 74 wedge base and replacing just the bulbs.
i cannot find anything that tells me if they are the same. I have the numbers for the later, but dont know if they are the same as my 87
next question is polarity. Are the POS or NEG common? i see on the board which conductor is common to the gauges, but dont know if that is + or- since our cars are ground supply.
my question is that on later model clusters you can get an entire socket assembly with the LED built in.
I want to go this route instead of buying the 74 wedge base and replacing just the bulbs.
i cannot find anything that tells me if they are the same. I have the numbers for the later, but dont know if they are the same as my 87
next question is polarity. Are the POS or NEG common? i see on the board which conductor is common to the gauges, but dont know if that is + or- since our cars are ground supply.
03-10-2014, 07:33 PM
#2
Electron Wrangler
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87-95 all use the same type of bulbs for main illumination (one type) and warnings (another type), the digi-dash model also use an extra type you don't have with a red cover.
Your last question on polarity doesn't actually make much sense.
If your LED lamp replacements are polarity specific (I believe all these small ones are, but some LED bulbs are engineered to be polarity independent), then as you can install them in either orientation you need to test to see that they work. Ed Scherer can likely confirm but I believe the orientation is not always the same for these in the different locations, either get the data on this or test before reassembly. I believe the positive supplies are most often commoned (e.g. warning switches switch to ground) but I have not checked all of these.
I don't really know what you mean by "Ground Supply" - eh?
Alan
Your last question on polarity doesn't actually make much sense.
If your LED lamp replacements are polarity specific (I believe all these small ones are, but some LED bulbs are engineered to be polarity independent), then as you can install them in either orientation you need to test to see that they work. Ed Scherer can likely confirm but I believe the orientation is not always the same for these in the different locations, either get the data on this or test before reassembly. I believe the positive supplies are most often commoned (e.g. warning switches switch to ground) but I have not checked all of these.
I don't really know what you mean by "Ground Supply" - eh?
Alan
03-10-2014, 08:24 PM
#3
Rennlist Member
Thread Starter
lol...sorry my jargon is so poor.....
by ground supply i mean that there is always powr supplied and the ground is supplied when the switch is activated.
the bulbs i am looking at are polarity specific. i asked this as i can tell the common on the printed circut board, just needed to know if it was + or -.
if all the warning lights, etc are the same for 87 and up,i am golden, i will order the complete assemblies.
thanks a ton.
i figured you would be the one to know... thanks again.
by ground supply i mean that there is always powr supplied and the ground is supplied when the switch is activated.
the bulbs i am looking at are polarity specific. i asked this as i can tell the common on the printed circut board, just needed to know if it was + or -.
if all the warning lights, etc are the same for 87 and up,i am golden, i will order the complete assemblies.
thanks a ton.
i figured you would be the one to know... thanks again.
03-11-2014, 12:33 PM
#4
Rennlist Member
FYI, you can use a 9volt transistor battery to test the LED's, and also power them installed in the PCB, the pos goes to positive, the neg goes to ground. This is covered IIRC in the write up's.