new tach/sending unit, but doesn't work?
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From: Bountiful, Utah
new tach/sending unit, but doesn't work?
Well i finally bought a tach. It is an isspro 2 1/16" EV 5k tach and i got the sending unit for our trucks too so i could plug it in. So I got it all hooked up and it doesn't work? The light on the tach works and comes on and everything, but the tach doesn't move like its not gettin a signal. So i unhooked it from the tach plug behind the fuse box and got my voltmeter out and checked the plug. I turned the key on and it showed voltage from the black switched wire. So i turned the truck on and checked the voltage from the Gray wire that gives the signal, and at idle it showed .15 volts and then if i pushed the throttle in, the voltage would come up to .20 and .25. So it is readin it isn't it??? Or should there be more voltage? Is the sending unit bad or how can i fix it? thanks
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From: Bountiful, Utah
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From: Mesa,AZ
Did you buy that little wiring harness they sell for first gens? Has 2 signal wires and the instructions tell you to use one and not the other. One has a "signal adapter" in it, and the other wire is just a wire. I bought this to work with my isspro tach, and it turned out mine did not want the signal adapter, just a wire.
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From: Buies Creek, NC
^^^^ What he said
I wrote about my experience with it here . . . https://www.dieseltruckresource.com/....html?t=173561
NOTE: If you're gonna run the ISSPRO gage that I have, do not waste your money on the ISSPRO adapter. To start with, the included instruction is backward in that it directs one to connect the 2 1/16" gage to the adapters white wire. As such the built-in filter component of the adapter is placed in the signal circuit.
Wired as such, the gage WILL NOT function.
The correct wiring has you connect the yellow wire which equates to a direct connection from the trucks PCM to the gage.
As such, the adapter amounts to an expensive 3' piece of four conductor wire with individual connectors on one end (NO molded plug for the OEM connector under the dash as some might think).
Save your money and use your own wire and connectors from Radio Shack.
Wired as such, the gage WILL NOT function.
The correct wiring has you connect the yellow wire which equates to a direct connection from the trucks PCM to the gage.
As such, the adapter amounts to an expensive 3' piece of four conductor wire with individual connectors on one end (NO molded plug for the OEM connector under the dash as some might think).
Save your money and use your own wire and connectors from Radio Shack.
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Joined: Jan 2009
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From: Bountiful, Utah
yeah i bought the wiring harness for our trucks from isspro and it has 4 wires with that are seperate and fit over the tabs on in the tach plug. it has the wire with the little filter and the one without the filter so i used the wire without the filter just like it said. It is a bubble faced gauge, the EV gauge, not the classic. so i shouldn't need the resistor right? I'll have to play around with it when i have more time.
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