Since my ALDL connector has been removed from my car, I was wondering where does it hook into the wiring harness? I'd like to try and get it back, but not sure how to put it back in. Since it is just a diagnostic port, does it just connect into the ECM? If anyone has info or pictures It would really help.

Thanks

 

It wires primarily to the ECM, but one terminal may go to the FP relay, one to the SHIFT lamp, and possibly another to the SES lamp on the IP.

 

I looked in my shop manual and any diagram is almost non existant. The only thing I found was in the back for the ECM troubleshooting. It shows 1 picture with the ALDL connector but it just shows it going into the wiring harness and doesn't show what wires actually go where. This is already turing out to be a PITA. When I took my lower dash apart I didn't seen any wires...I don't know how or why someone would cut it out. You would think if they did cut it out , they would at least leave some wiring but I don't see anything.

 

It may have been cut loose right back at the ECM connectors.

 

There is a connector under the passenger side dash that has all the wires cut. I still don't really know what it is. This weekend I'm going to really look under the dash and see what all is missing and what is there.

 

That's where the ECM should be. Are you certain that it is present and connected?

 

Here is my original thread on the subject with photos.

Check out this hackjob

 

Oh.

That's sad. Someone has hacked out your ECM. That is where is is supposed to be mounted. The second photo appears to be the buffer/inverter module for some of the ECM's I/O points. The CCC ECMs were semi-standard (like the 1224810), in that a single ECM could be used on many models, but around '81-'82 the different ECMs came out (like the '459), and functions like the MC solenoid, EGR solenoid, and TCC were hard wired for logic opposite that of very early ECMs.

In your car, the ECM would control primary fuel mixture, spark advance, TCC or SHIFT lamp operation, EGR operation, AIR injection, idle load control, and possibly a A/C compressor cut-out relay. It would require inputs from a TPS, VSS, O² sensor, detonation sensor/EST module, distributor pickup coil/HEI module, neutral safety switch, brake pedal switch, fourth gear switch, MAP/BARO sensor, and CTS.

You may have a little work ahead of you to return it to normal.

 

TPS is on the throttle bodies
the VSS is behind the speedometer
Don't have an 02 sensor, but that's not hard
EST modual is part of the distributor...which I will have to get
Neutral safety switch is on the shifter
Brake switch I have
4th gear switch...not sure. My car originally was a 3spd Auto. It's now a 700R4
Map sensor I will need
CTS...not sure what that is either.

I don't think it'll be that hard...it's just that I need to find a good wiring harness that hasn't been cut. Complete from the engine to the ECM. I have read on the Crossfire Vault that some people switch out their ECM's for ones that came in 87-91 Chevy Trucks. There is another one from Caprices also. I guess they allow better tunability. Also there is a wiring harness available from "Painless" for '87-'91 throttle body setups. I was thinking it should be a pretty direct replacement, but they are expensive. That is why I'm trying to get a stock one cheap

 

The TPS is in the carburetor, with a connector at the LF corner.

Unless you've changed distributors, the EST module should be a separate unit on the firewall. The HEI is part of the distributor.

The 4th gear switch would have been the "top gear switch" on a TH350 or TH200 trans installation.

CTS is a coolant temperature sensor, separate from the one used to operate the dash guage.