As the title reads, I would like to make my gauges in the stock cluster work again. Currently the only one that works is the speedo(mechanical) The computer has been completely removed and the car is currently running aftermarket gauges. I would like to somehow wire the original gauges to work with their respective sensors. Is it as easy as finding the point on the circuit board and running a wire for each?

 

It's probably even eeeeeeeezier than that.

Since the computer is not connected to gauge operation in any manner way shape or form, that's irrelevant.

Tackle it logically, step by step. Don't just jump into the middle of a hack job and add more hack jobs on top of it. Do it RIGHT.

Step 1 would be, to figure out what the PO did when they hacked the other gauges into the car. Step 2 would be to un-do ALL of that. Step 3 would be to hook all of the car's gauge wiring back up just like it came from the factory.

Tackle Step 1 first. My guess would be, all they did (this being the typical hack job) was unhook the factory wiring and leave it laying there. Messing with the dash is MUCH harder and therefore most hack-job hackers won't bother; the usual reason they hack cars up instead of repairing or maintaining them properly in the first place, is because they're lazy, and hacking seems easier than doing stuff right, at least right at first. But it's too dark for me to see the car right now well enough to tell you what they did to it, maybe after the sun comes up... you'll just have to get out there and investigate.

Step 2 is pretty straightforward. If it looks like a hack job, IT IS. Get rid of it. Find all the factory wires, make sure they're not cut; if they are, go to the junkyard and get the right ends off of ANY GM car or truck of about the same age, just go by the color of the wires and the place they plug in to. (temp sending unit, oil pressure sending unit, etc.)

Step 3 would involve taking out all the aftermarket sending units and putting all the factory sending units back in, and plugging them all back up. Not too tough.

Wouldn't hurt to check the Gauges fuse somewhere along the line, who knows whether that's even still in there.

I'd strongly suggest leaving the circuit board and all such as that, as alone as possible. I seriously doubt they touched any of that. If they did, just get another one; find a dash on the classifieds on this site or something. Those things are fragile enough just on their own, I can't imagine being able to successfully "repair" one after it's been hacked up.

 

It is not a hack job as I am the one that removed the ENTIRE wiring harness neatly and clean. I did this to preserve its integrity since the computer fried on me. I still own the entire harness as well. The mechanical gauges are are installed clean as well. They are not hacked in.

My question is can I get the original gauges to work without reinstalling the entire wiring harness?

My only issue with reinstalling the entire harness is the great amount of leftover wiring that would have to be tucked away. I think it would be easier to just wire the gauges with new wire.

 

When you removed the ENTIRE harness, you must be referring to the ECM harness that passes through the right fender?

None of the gauges use that harness. They are all connected to the engine harness that passes through the bulkhead connector at the firewall. Since this harness is required for other vital engine functions, I assume you didn't remove it, hence not sure why your gauges no longer work.

 

Yes, I only removed the harness that passes through the right fender. I guess I need to dig into my book and find out where exactly everything runs. I did remove the gauge cluster when I was troubleshooting why the check engine light was not coming on like it should. I did that at the same time i removed the wiring harness so I wrongfully assumed they were connected to each other. If I remember correctly I did have a burnt spot on the connection from the wiring to the gauge cluster. I will check it out and let you know.

Sounds like there is hope that I could get my stock gauges to all work.

A Side question. I have my tach wire hooked up to the brand new accel dizzy but the tach doesn't move. It didnt move with the old setup either. Is this just a simple wire to the gauge cluster? (I am trying to find my haynes book as I type this)

 

I'd suspect loss of power to the cluster.

 

Right: the wiring that goes through the right side of the windshield cowl is for the ECM, and is not connected in any manner way shape form or fashion to the gauges.

ALL of the gauge wiring is in the connector under the brake booster. (well, except for the gas gauge wire... that one is in the "Fisher Body" connector under the carpet near the clutch pedal)

Sounds to me like, if the underhood wiring is all still there and intact and good and hooked up to the correct sending units, but ALL the gauges still don't work including the tach and gas gauge, you have a problem in the 12V power feed to the whole cluster. I'd start by checking your FSM for which pin of the cluster connector is 12V, and check that pin to see if it's there. Of course, check the obvious first, like the gauge fuse.

 

Would that affect my gauge lights as well? They all work and my seat belt light does light with the key turned on, the buzzer even works.

 

Look in the wiring harness near the brake booster. There should be a dark green wire that is for your coolant temp sensor and a brown wire for the oil pressure gauge. I believe the tach wire is white or grey. Get the proper sensors from the auto parts store and install them. An 84 L69 should be a one wire sensor just make sure you get the right oil pressure sensor. There are different ones for a 60 or 80 PSI gauge.

What did you do with the distributor after you removed the computer?

 

gauge lights are fed from a different circuit, getting their power from the headlight switch thru the cluster lights fuse. hence the ability to dim them at the headlight switch.

 

I installed an Accel distributor with mechanical vacuum advance. The tach should still work with it correct? I still have the original dizzy and electronic quadrejet as well as the entire harness

 

You will need to connect the wire and possibly wire in a 10kohm resistor or a tach filter.

 

Is there a method for checking to see if the tach is good before I go through the trouble of wiring in a resistor? Does it go in series or parallel?

 

Yup make sure it has power and ground then apply 60hz to the signal pin and it should read 900 rpm. Series.

 

Make sure it's 60 Hz at around 12V P-P (around 5V RMS); not for example, 120V RMS.

 

Any suggestions on how to make that exact RMS and Hz? I do not own a signal generator.

 

A small transformer