84 warning ligh cluster not working
Thread Starter
Instructor
Joined: Jul 2013
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From: Hoxie Kansas
84 warning ligh cluster not working
I have a 84 vette and the center cluster where all the warning light are nothing works. Well only the security light flashes. Took it apart and the bulbs seem good. Check fuses and they are all good. Any ideas?
Racer
Joined: Aug 2013
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Does the check engine light come on when you turn on the key without starting the engine? With the security light operating, you could test all of the bulbs in that socket, sometimes it is hard to tell if a bulb is burned out or not.
Race Director
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From: Whitefish Falls Ontario
St. Jude Donor '08-'09
Did you check for voltage on both sides of the fuses, most only powered through the gauge fuse with the key in start or run.. The other possibility is a missing ground. 
Thread Starter
Instructor
Joined: Jul 2013
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From: Hoxie Kansas
I did switch the check engine and security light bulb. No lights when the key is in the start or run position. I just check the fuses. I will check teh volts and see what they read.
I do have a ground wire coming off the back of the motor. I do not know where it goes.
Where does the ecm ground go? Or what color is it and I can run a new ground wire.
thanks again
I do have a ground wire coming off the back of the motor. I do not know where it goes.
Where does the ecm ground go? Or what color is it and I can run a new ground wire.
thanks again
Racer
Joined: Aug 2013
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On the white (24 pin) connector on the ecm, you should have ground at pins 6, 12, and 13. There should be more than one wire at your ground point at the back of the motor. The original location is one of the bellhousing bolts, but it seems like most of the time it gets moved up to one of the intake manifold bolts. With the key on, the gauges fuse supplies power to the center cluster on the pink wire with a black stripe at the cluster connector. The ecm provides the ground to light up the check engine light, which should come on any time the key is on and the engine is not running. Does the car start and run right now?
Thread Starter
Instructor
Joined: Jul 2013
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From: Hoxie Kansas
yes car starts and runs. It runs rich and idle is rough. It smooth out a bit went you tap the little leaver behind the TBS. It gives it a little shot of gas.
I tried to get a local mechanic to try to put his computer on it but he did not show up to day. My buddy was telling me about checking the codes with the check engine light blinking but I got to get it to work be for I can check it.
Is it common for the ECM to go bad? My thoughts are that it is a bad ground.
How do you count the pins? Start at the top and go to the right and then go down to the next row?
thanks again guys
I tried to get a local mechanic to try to put his computer on it but he did not show up to day. My buddy was telling me about checking the codes with the check engine light blinking but I got to get it to work be for I can check it.
Is it common for the ECM to go bad? My thoughts are that it is a bad ground.
How do you count the pins? Start at the top and go to the right and then go down to the next row?
thanks again guys
Race Director
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From: Anaheim CA
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Racer
Joined: Aug 2013
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The pins on the ecm connector are numbered. Look near the top of the connector next to the shroud, there will be numbers 1 thru 12 on one side and 13 thru 24 on the other. The check engine light gets the ground from the ecm, and 12 volts any time the key is on, check for 12 volts first, then if you are not getting a ground signal from the ecm, check for continuity to pin 20 of the white ecm connector.(also connects to pin E of the aldl) On the center cluster connector, the 12 volts will be on pin 15, and the ground signal from the ecm will be on pin 17. The center cluster connector is also numbered. (All connectors will be numbered or lettered, just sometimes hard to see)
Thread Starter
Instructor
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From: Hoxie Kansas
Guys thanks for all the help.
We got it fixed to night. Lots of chasing wires and checking for good ground and power.
To make a long story short it was the power wire from ECM to the cluster connector.
I now have all my warning light working. Check the car for codes and it was clear. code 12.
I do have a quick question
The car idles at around 900 and smell pretty gassy. Any ideas why it want to idle that fast? Or is that normal.
Thanks again for all the help.
I almost thought for a little while that I would never get it fixed.
We got it fixed to night. Lots of chasing wires and checking for good ground and power.
To make a long story short it was the power wire from ECM to the cluster connector.
I now have all my warning light working. Check the car for codes and it was clear. code 12.
I do have a quick question
The car idles at around 900 and smell pretty gassy. Any ideas why it want to idle that fast? Or is that normal.
Thanks again for all the help.
I almost thought for a little while that I would never get it fixed.
Racer
Joined: Aug 2013
Posts: 301
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Next step is making sure you have no vacuum leaks, followed by checking the base timing, setting minimum air and balancing the throttle bodies, then resetting tps voltage, assuming the IAC's work.
Racer
Joined: Aug 2013
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Forgot to mention - finding out if your IAC's work should be done before everything else. I'm not exactly sure what an easy test for the IAC's would be, hopefully someone else will chime in here. I would think you could pull the IAC, and with it hooked up, it should extend all the way with the key on and a jumper between A and B of the diagnostic connector, and it should retract when turning the key on with the jumper removed.
Last edited by nobodycls; Jan 26, 2014 at 08:41 PM.
