91 tbi no wires in d1 or d2

[bigcountry]

Hi everyone! So I have been reading and searching diagrams both in books and online for days now preparing to do my swap. I have a 1991 k5 blazer and am putting a 2004 gmc sonoma body on it. I unbolted the bulkhead connector from the body of the blazer and pulled the ecm and wiring. The only wires I cut were running to the aldl I believe. They break out of the bundle about 6 inches from the ecm connectors and go to a white connector running to the driver side of the blazer. Every schematic shows D1 and D2 going to ground. Problem is I have a tan wire in D1 and a purple wire in d2. When tested with a meter i have grounds at D1 and D6. Any help you can provide would be greatly appreciated.

[brian617]

Try pulling the BLUE and GREY combs (terminal retainers) out and look at the letters and numbers on the actual connector itself.

[Nasty-Z]

Hi everyone! So I have been reading and searching diagrams both in books and online for days now preparing to do my swap. I have a 1991 k5 blazer and am putting a 2004 gmc sonoma body on it. I unbolted the bulkhead connector from the body of the blazer and pulled the ecm and wiring. The only wires I cut were running to the aldl I believe. They break out of the bundle about 6 inches from the ecm connectors and go to a white connector running to the driver side of the blazer. Every schematic shows D1 and D2 going to ground. Problem is I have a tan wire in D1 and a purple wire in d2. When tested with a meter i have grounds at D1 and D6. Any help you can provide would be greatly appreciated.

D1 is a system ground (Meaning actual vehicle ground) probably originally attached on the rear of the cylinder head or at the thermostat housing .
D2 is a sensor ground and with the purple wire you suggest is in there I would say MAP sensor is using this pin.
D6 is the O2 sensor ground and would attach along with D1 either at the rear of a cylinder head or at the thermostat
A12 is a system ground similar to D1 as to where it connects
A11 is a sensor ground and is used for the TPS and CTS in your application I would imagine.

A note : A11 and D2 are paralleled in the ECM so it is basically the same sensor ground , just what GM wanted to connect to either / or .

If all the harness is intact , I would simply reconnect the grounds as they were removed , you should be fine.

HTH

TOM

[bigcountry]

Thanks for the replies. I never disconnected anything from the engine or chassis. I layed the ecm and wiring on the engine and lifted the old body off. I was hoping it would be as simple as finding which wires at the bulkhead connector needed power and ground and just applying it there but 8 guess no such luck. I haven't been able to find a diagram for the bulkhead connector.