2000 Cavalier Coupe, Viper 791XV

Hello all. I have a 2000 Chevy Cavalier 2 Door Coupe and I am in the process of wiring it all in. I have found all of my wires except my tach signal wire. I've read all of the posts about this topic on this website but none of the wires seem to be working for me. I am testing for AC voltage on the PURPLE / White wire in the engine harness at different points and it reads out .8 Volts AC. Same result for the white and orange wire. My car is an automatic but it has a working tachometer. I haven't found that wire under my dash yet, and am unsure whether it work or not. I've read about the option to use my fuel injector wires instead but they are buried under a steel plate and my intake assembly. I seen one other 2000 Cavalier / Viper setup but he never posted his findings. Thanks for your time.

 On the 2.0 theres a harness that runs over the transaxle. It has 2 white wires in it. One is the tach. The 2.2 theres aplug on the distibutor...it has 6 wires on it. Use the white one

Thanks for the reply. I have the 2.2L and have tested the white wire with no luck. I am testing for AC voltage and grounding to the chassis. I should be getting a reading of 1-6 Volts and it should fluctuate with the RPM's correct? When I test this wire I only get about .8 Volts. I'll retest it and see if it will work for me this time. Thanks again.rekon

Well I have retested that white wire and it does not read in between 1 and 6 Volts AC. When the car is off its at about .05 and when idle its up around .120 and goes up as the RPM's go up so its apparently my tach or some engine speed measurment. My first question is the input is never a solid number, always changing but usually averaging out. I suppose this is normal due to all the electrical noise. Is it? My second question is though it seems to be the tach wire, it's not showing above 1 Volt. Will this effect the functionality? Thanksrekon

the white wire is the right one, you need to put one lead of your meter to 12V and the other to the tach wire as these are negative pulses.Shaughn Murley

Install Manager, Dealer Services

Visions Electronics

Red Deer, Alberta

Thanks for the information. I still cannot seem to get the 1 to 6 volts I've been reading I need but I have tapped into that wire and ran it to the alarm module. I'll post back here my end result in a few days (I have to wait on door pin switches and passlock bypass.)rekon

just curious what the actual "problem" is... since no one has brought it up....    did you try tach learning and it didnt learn?    both the white or PURPLE / white should be fine.....Kevin Gerry

Certified Electronics Technician

MECP First Class Installer

Owner/Installer

Classic Car Audio

since 1979

Hasn't become a problem yet. I'm waiting for the UPS guy to give me my passlock bypass so I can finish hooking it all up. I was worried about using the white wire because when I test it with a DMM it reads under 1V AC. The manual says it should be ~1-6V+ AC. The readings show between .300 and .900V AC and changes with the engine speed so I'm pretty confident that this is the wire.

rekon wrote: Hasn't become a problem yet. I'm waiting for the UPS guy to give me my passlock bypass so I can finish hooking it all up. I was worried about using the white wire because when I test it with a DMM it reads under 1V AC. The manual says it should be ~1-6V+ AC. The readings show between .300 and .900V AC and changes with the engine speed so I'm pretty confident that this is the wire.

Bingo!!!!!

if it flauxs up and down to  a degree like your saying its it

did you have any problems wireing the door locks