In need of a pinnout diagram of the main engine/body harness for the C202 connector, I'm going through installing a standalone ECU and some other goodies on the good ole ****box and it came with its own standalone harness to run to its sensors and new bits but I'm opting to use the original cluster as well instead of just the standalones dash/tablet thing. Im pulling the entire OEM harness out and going to be building a new custom harness for the engine bay to incorporate the new harness provided and the original sensors along with AC connections and im starting to go crosseyed staring at this thing all stripped down with all its different sub connections and splices. If anyone has the pinout for the C202 connector in the firewall and wiring diagrams for this harness that could get it to me I would be so grateful. I have dug through the deps of all data, identifix, charm.ly, and prodemand and came up with nothing for the pinout

 

I can't find one either, but am not sure why you would need it? Those early year trucks, the computer/fuel injection system was mostly separate from the main truck's harness. There were cross-overs, for some clutch or transmission switches, some speed sensors if you have one. But 90% of the computer/fuel injection was a separate harness that you can remove without too much trouble. There will also be some power and ground tie ins over near the battery.

I just did a 1984 Bronco II. Pulled out the carbed computer system, and installed another system from a later 1986. Pulled the 84 computer, then took the large computer connector and got it through the firewall. Then started gently pulling on it, anything connected to it, I disconnected it. It still cranked, all the lights still worked, heater and all that still worked, no work needed in the fuse box. Then I took the 86 fuel injection and installed it, it had a mostly separate harness also. The only wires I had to figure out were the ones to the transmission switch, and had to add some for the fuel injection fuel pumps. Had a couple of powers and grounds over by the battery. That was it.

 

The main harness and engine sub harness both have different sensors and components off of them that I need and wanting to separate them from the harness to include in the new one to avoid having so much clutter in the engine bay

 

I am sure you have it in front of you and have everything marked. But I have not seen that on the older vehicles. For instance the oil pressure, water temp, sensors for the gauges in the cluster are part of a totally different harness. The water temp sensor for the computer is with the computer harness. So you should have two water temp sensors. When you get a little bit later in the early 2000's, this is not true anymore.


I am assuming you want to get rid of the computer harness, but keep everything else.

 

Oh if only you could see the giant ball of spaghetti I have in my garage floor right now XD yeah im trying to do away completely with the PCM harness and have it as bare bones as can be to avoid clutter, the AC compressor, oil pressure, and coolant temp sensors "little barbed one wire one for the gauge" all run through the engine sub harness that disconnects from the 4 plugs on the main engine harness on the left fender liner but the main engine harness has wires that run all the way around behind the grill to the other side to the MAP sensor and im assuming the leads off for the compressor cycle/pressure switch and command wire for compressor. Im also doing away with the oem O2 sensor and needing to install two new sensors "wiring is in the new harness" so I'll do away with those as well. I went ahead and ordered the 1991 Ford trucks wiring diagrams book on ebay as well as a digital copy for the EVTM which sadly does not have the pinnout for this connector. I plan on having a main engine harness and sub harness now but it be wired along side with my new harness. Im an almost master tech right now and been wrenching professionally for about 10 years now and haven't dabbled in classics/custom work but have had to work on them in the past and the absolute headache of rats nests people do for "restoration projects" makes me physically ill so I swore to myself when time comes to what I'm doing now I'll do it right and make it look factory with new diagrams or following OEM wiring diagrams as closely as physically possible.

 

That is weird. On most Fords the PCM harness is separate and comes in on the passenger side. A lot of the computers for those years are mounted on the pass side kick panel area in the interior. You mentioned the O2 sensors, and that is usually one of the tie-ins to the rest of the truck harness, for power to the O2 sensor heater circuit. But the O2 sensor wire itself is part of the PCM wiring.

 

87 I believe to 91 first Gen EFI the PCM and C202 connector are side by side on the driver side like through the firewall under the brake booster and cruise control controller thing. Before that they're in a different location and next generation they're in the same spot but use a totally different harness/connector

 

I looked it up on charm, the factory PCM is on the driver's side of the engine compartment correct? Was it in the engine compartment, or behind the dash and the connector stuck through the firewall?

 

Both the C202 connector and the PCM are on driver side firewall correct. Unfortunately charm only has the PCM connector pinout tho

 

The only way I know that you are going to be able to do it, is by wire color and process of elimination. For instance I looked up on charm, electrical diagrams, power distribution, battery, and the diagram below came up. I see a fat yellow wire that feeds the fuse box, and it does go through C202 according to the diagram. Looking further down in the diagram, I see another yellow wire that goes through C202 and feeds the ignition switch. To the left in the diagram I see another yellow wire going through C202 that feeds the rear window defrost switch Further down in the diagram toward the right, there is a black/orange that goes through c202 that feeds the headlight switch and a fuse in the interior fuse box. Even further down on the right I see a red/lightgreen that is leaving the ignition switch, going through C202, and then feeding the TFI, EEC relay, ignition coil.

 

2nd diagram'

 

3rd diagram. I think I see a c202 I might have missed feeding the stoplamp and hazard flasher.

 

I seem tedious, but I think with some masking tape as wire markers, you will get it eventually.