Gauge cluster MPH/KmPH light?
Thread Starter
Burning Brakes
Joined: Sep 2003
Posts: 875
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From: Louisville KY
Gauge cluster MPH/KmPH light?
Ok, I'm sure no one will have an answer for this but its worth a shot because I'm getting a little frustraited... I'm using the C5 IPC in my C4 LS1 conversion.... Everything is wired up and works fine (Fuel level won't function until I create my own conversion circuit) but I can't get the stupid MPH/KmPH indicator light to come on! I had it on before while bench testing but I can't remember what I did for the life of me! Its not that big of a deal but I would really like it to function without me "customizing" it... lol
First, I AM NOT USING THE BCM so everything is manually inputed directly into the IPC other than anything that it recieves through the serial data line (pretty much all gauge signals). Anyone have a very, very good understanding of the IPC and the internal workings...and whats what? Delco techs perhaps?? lol I have the basic block diagrams from service manuals but they don't give me an idea of how the MPH indicator light illuminates... don't even have anything in the manual from what I could find. Any thoughts are much appreciated.... Thanks
Scott
First, I AM NOT USING THE BCM so everything is manually inputed directly into the IPC other than anything that it recieves through the serial data line (pretty much all gauge signals). Anyone have a very, very good understanding of the IPC and the internal workings...and whats what? Delco techs perhaps?? lol I have the basic block diagrams from service manuals but they don't give me an idea of how the MPH indicator light illuminates... don't even have anything in the manual from what I could find. Any thoughts are much appreciated.... Thanks
Scott
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
OK I'll accept the challenge, but I'm probably not going to have the magic answer.
The MPH/kph indicator is internally powered from what I've been able to find in the service manual. It should illuminate based on power being provided to the IPC wiring harness (note there are 2 pins for +12V and 2 pins for ground).
But it appears it may also be looking for +5V reference voltage from the DIC Switch 5 (E/M button). That signal is normally +5V until the button is pressed momentarily (grounds the circuit) to toggle the lamp from MPH to kph. But it seems to expect the +5V in steady state. Are you doing that?
Other than that, you're right - the manual does not show further details internal to the IPC.
Good Luck.
The MPH/kph indicator is internally powered from what I've been able to find in the service manual. It should illuminate based on power being provided to the IPC wiring harness (note there are 2 pins for +12V and 2 pins for ground).
But it appears it may also be looking for +5V reference voltage from the DIC Switch 5 (E/M button). That signal is normally +5V until the button is pressed momentarily (grounds the circuit) to toggle the lamp from MPH to kph. But it seems to expect the +5V in steady state. Are you doing that?
Other than that, you're right - the manual does not show further details internal to the IPC.
Good Luck.
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
After my unfortunate incident with a defective battery charger where I shot 128VAC into the IPC, I have learned a LOT about the IPC. Way more than I ever wanted to know! The MPH/kMPH lamps is driven by the internal logic of the IPC. The question is does the lights not light at all, or will it not change? And does the values like oil press and temp on the DIC change between English and Metric when the E/M DIC button is pressed?
Also, a GM tech won't do you any good on this either. You would have to find a cluster repair center to get detailed info on the internal workings of the IPC. I'm not sure how good they document the IPC for these centers but GM works hard to put proprietary numbers on all the components inside the IPC so no one can identify the parts they use.
Also, a GM tech won't do you any good on this either. You would have to find a cluster repair center to get detailed info on the internal workings of the IPC. I'm not sure how good they document the IPC for these centers but GM works hard to put proprietary numbers on all the components inside the IPC so no one can identify the parts they use.
