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Factory Tach wiring??
I have a factory tach that has not worked since I bought the truck. Today while saying many many bad words pulling out the headlight switch that burned up this morning I found the factory tach had the wire just hanging about 6'' below the tach. Anybody know what goes to what? There are 4-yellow wires----1 red wire-----1 grey wire----1 black wire. Any ideas?? The headlight switch is a bugger to get out when the time comes guys. Mine has worse problems tho--the plug is melted way gone.
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your tach wire does not have a plug on the end ?? just wires ?
it should have a plug that hooks up to the male part of the plug coming out of the harness, next to hood latch tied around the main harnes. |
The OEM factory tachometer plug offers the following:
- 18ga Black = +12vdc for gage lights - 20ga Orange = 12vdc Common - 18ga Red = Switched +12vdc - 20ga Grey w/light blue tracer = Tachometer Signal From PCM The following schematics show where the above comes from. The images are high resolution so you can zoom in to make them out better. ;) OEM Tachometer ~ +12vdc f/Lights / -12vdc Common https://www.dieseltruckresource.com/...2vdcCommon.jpg PCM Signal To Tachometer https://www.dieseltruckresource.com/...gnaltoTach.jpg Switched +12vdc To Tachometer https://www.dieseltruckresource.com/...2vdcToTach.jpg Hope this helps. :) |
Originally Posted by BC847
(Post 2613733)
The OEM factory tachometer plug offers the following:
- 18ga Black = +12vdc for gage lights - 20ga Orange = 12vdc Common - 18ga Red = Switched +12vdc - 20ga Grey w/light blue tracer = Tachometer Signal From PCM The following schematics show where the above comes from. The images are high resolution so you can zoom in to make them out better. ;) OEM Tachometer ~ +12vdc f/Lights / -12vdc Common https://www.dieseltruckresource.com/...2vdcCommon.jpg PCM Signal To Tachometer https://www.dieseltruckresource.com/...gnaltoTach.jpg Switched +12vdc To Tachometer https://www.dieseltruckresource.com/...2vdcToTach.jpg Hope this helps. :) |
No. The black wire is a ground wire for the rheostat controlled dash lights. The orange wire is the rheostat controlled positive feed for the lights.
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Originally Posted by Angry Johnny
(Post 3345785)
No. The black wire is a ground wire for the rheostat controlled dash lights. The orange wire is the rheostat controlled positive feed for the lights.
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Originally Posted by 1stGEN'93
(Post 3345790)
Sorry for my stupidity in wiring and electrical, but what is a rheostat? To wire my gauge I actually need a 12 volt constant (gauge has a memory feature), 12 volt switched, a dimmer, and a ground. If you need a constant 12v key off and on you'll need to find a wire at the fuse box or take it directly off the battery. |
Originally Posted by Angry Johnny
(Post 3345801)
The rheostat is on the headlamp switch. That is what enables you to vary the intensity of the dash lights.
If you need a constant 12v key off and on you'll need to find a wire at the fuse box or take it directly off the battery. |
LED don't typically dim like incandescent bulbs do. They may need a 12v trigger from the head lamp switch. The orange wire will not work for that.
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Originally Posted by Angry Johnny
(Post 3345814)
LED don't typically dim like incandescent bulbs do. They may need a 12v trigger from the head lamp switch. The orange wire will not work for that.
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Originally Posted by 1stGEN'93
(Post 3345816)
The instructions from the gauge packaging said not to wire it to the headlight switch, because it will make it flicker. |
Originally Posted by Angry Johnny
(Post 3345837)
The Max Tow gauges I have said to not wire it to the dash light wire but to use a constant 12v source from the switch, like for the park/tail lamp wire.
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Originally Posted by 1stGEN'93
(Post 3345846)
I misread the directions. I have the GlowShift 3-in-1 gauge and it says I need a constant 12 volt switch like the radio, a ground, a 12 volt switches or key-on power, and a dimmer hooked to the headlight switch, but not a dimmer wheel. Looking at my factory tach wiring harness on my ‘93 I found it does not have the same wire colors. It has two black wires, a orange wire, and a light blue wire. I guess I will have to decipher the wiring diagram in my FSM. Electrical is not my forte, so maybe I’ll have to enlist the help of a friend who gets it. Also make sure you have the correct connector. Sounds like you might be looking at the trailer brake connector. |
Originally Posted by Angry Johnny
(Post 3345854)
That is what it means. It just needs to know the lights have been switched on and then the gauge dims the light. So use a tail/park lamp wire to tap off of.
Also make sure you have the correct connector. Sounds like you might be looking at the trailer brake connector. |
Yes it does. That's the orange wire.
As a general rule on Chrysler products red is battery hot, blue is ignition hot, orange is dash lighting and black is ground. There are always exceptions though. |
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