last few wiring questions on LS into 84 Vette
07-18-2014, 01:23 PM
#1
Staging Lane
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last few wiring questions on LS into 84 Vette Ok swappers...
I'm hooking up the last few wires on my swap and have questions....
1. My 84 has the digital dash (no I'm not swapping it out, so don't go there). The VSS on the old drivetrain went into the digital speedometer first, and then to the ECM. On my new LS ECM I have a wire out from the ECM location 60 which goes TO the speedometer. Question....do I just hook the ECM out to the speedometer input? Or should I hook the VSS to the speedometer input?
2. I have a dk green/white wire from location 17 on the ECM labeled as AIR Con request. I was going to hook that to circuit 66 on the car which runs directly to the pressure cycling switch to close the A/C circuit. I think, anyone have clarity on that?
I'm hooking up the last few wires on my swap and have questions....
1. My 84 has the digital dash (no I'm not swapping it out, so don't go there). The VSS on the old drivetrain went into the digital speedometer first, and then to the ECM. On my new LS ECM I have a wire out from the ECM location 60 which goes TO the speedometer. Question....do I just hook the ECM out to the speedometer input? Or should I hook the VSS to the speedometer input?
2. I have a dk green/white wire from location 17 on the ECM labeled as AIR Con request. I was going to hook that to circuit 66 on the car which runs directly to the pressure cycling switch to close the A/C circuit. I think, anyone have clarity on that?
07-18-2014, 05:43 PM
#2
TECH Fanatic
I am not positive on the speedo question, but have you tried to wire from the VSS output just like the original? I take it you are using a 4L60E?
I am pretty sure that the AC request should set up as you describe. If not someone here will let you know. I have mine set up so that when the AC circuit is energized it triggers the AC request.
I am pretty sure that the AC request should set up as you describe. If not someone here will let you know. I have mine set up so that when the AC circuit is energized it triggers the AC request.
07-18-2014, 09:23 PM
#3
Staging Lane
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The original VSS went into the display directly. The new one comes is attached via harness to the computer first. I'll try both ways unless someone responds with answer.
07-19-2014, 09:34 AM
#4
1) LS1 PCM output is 4000ppm, most older electronic VSS are 2000ppm. You might need a dakota digital box to step down the signal so the speedo can understand it
2) Find a wire from your HVAC head unit that is 12v when in the AC/defrost settings. This is AC request. Most GM cars have an separate harness for HVAC and its often the light blue wire
2) Find a wire from your HVAC head unit that is 12v when in the AC/defrost settings. This is AC request. Most GM cars have an separate harness for HVAC and its often the light blue wire
07-19-2014, 10:48 AM
#5
Speedo I just got done wiring my VDO speedo and used the wire directly from the ECU and it works fine. Several different ways to calibrate the speedo, one is a measured mile and the other (for mine) was pulses per mile. On my older 33 ****** with an LT1 I piggy-backed the signal directly from the trans output. In any case older electronic speedos required a specific number of pulses but newer ones are able to adapt to the application. If you don't have the paperwork on your gauges I would try the wire from the ECU. Most likely it will work fine.