I installed an '88 Camaro IROC interior in my 80 El Camino. I converted the existing El Camino idiot light instrument panel to the full gauge Camaro cluster. Sensors were changed, additional pink/blk wires and grounds were added as required for the Camaro cluster. GM was pretty smart by maintaining the same color codes for all the instrument panel lights, fuel, brake light, turn signals, high beams etc. so it was pretty easy to convert the Camino single cluster plug to the dual Camaro cluster plugs. What the Camino didn't have was a tach but that was pretty easy to connect to the distributor. I've just spent several hours verifying all my cluster contacts and traced them out. I did this entire conversion about 10 years ago and had been living with a couple of gremlins. Everything works ok but my voltmeter reads lower than the battery voltage and the tach bounces a few hundred rpms everytime the turn signal is flashing. Since I'm redoing my interior I thought I'd pull the dash and cluster out and check the wiring. I have an 87' instrument panel wiring schematic and it shows that the voltmeter is connected to the brown wire coming from the alternator on pin 14 of one of the two connectors on the back of the Camaro cluster. Right now, the voltmeter is reading the voltage that feeds all the instruments in the cluster on one of the four pink/black wires that are connected to the cluster. My '88 factory manual doesn't have a wiring diagram. My 88 cluster plastic mylar circuit board does not have any connectivity to anything on pin 14, it's blank. I have a second cluster from an '88 and it's the same way. I'm trying to confirm if the voltmeter does in fact measure the voltage from the vehicle instrument cluster and not by measuring the voltage directly from the alternator via the brown wire. I've searced for quite some time for a schematic including AutoZone. I'm checking all my grounds but it's dark outside now. That could be the source of my trouble but was really interested in seeing a schematic for an '88 Camaro cluster. I'm surprised the wiring is different between an '87 and '88. I'm running a 350 TPI, not that that makes much difference. Any help is appreciated.

Art in Reno

 

Well I haven't found any '88 Camaro schematics but I do have them for an '87. I don't know if the Camaros with gauges also have a generator light. I have one wired to mine and it's on the RH side of the cluster next to the steering column. It's blank, but red. My brown wire from the generator is connected to one side of the lamp and the other side of the lamp is connected to switched power. When the voltages oppose the light is out. When the ignition is turned on and the engine is not running the light is illuminated because the generator is not turning. Also bridged onto the brown wire may be resistor wire (10 ohm) terminating on the ignition switch orange wire. This circuit has something to do with illuminating the light and may also be the exciter wire for the alternator. So after doing some more research it seems the voltmeter does read system voltage from the switched power going to the gauges. I've been doing some other cleaning up on the wiring with the alarm, remote start, auto window rollup, anti-grind relays and some other wiring in order to tidy up the underdash wiring. Now that the dash is out it's easier to work on the wiring. I discovered that several grounds were not terminated directly to the body metal but were grounded though a threaded body clip and a threaded bolt. This body clip is similar to the clips that holds fenders to the inner panels on some vehicles. Since the body is painted it may not have been a solid ground. I won't know if this fixes by gauge bouncing issue but I'll move these grounds to a solid ground. I traced all my wiring to the cluster gauges and nothing was out of the ordinary. It seems to be wired the way it should be. I'll know more when I finished tidying things up and fire up the car. I know this may be boring to some of you but I enjoy a puzzle and installing the Camaro dash, dash cluster and TPI to the Camino has been very challenging.

Art