v8 swap, car wiring harness?

hmn4389

New Member
how come when you swap a 4.6 into a v6 you need the cars wiring harness from the headlights to the taillights? what does the ecu control there? is the same required if a 5.0 was swapped in?
 

hmn4389

New Member
you will need a wiring harness for most engines, unless you get a carbed one
im not talking about the engine harness, im talking about the entire car. like headlights and taillights, i read somewhere when swapping a 4.6 you need to rewire all of that stuff. i was wondering why
 

bigdogcq

I paint the M's on M&M's
The wire harness from the 5.0 based cars (95 and prior) is not compatible with the 4.6 based cars (97+).

I believe there are ways to make it work but its an excessive deal.
I switch the whole harness headlight to taillight when I swapped my 03gt motor into my 95 v6. (note) Door harnesses are different as well

I know alot of plugs are the same in terms of the actual plug in to the headlights, tail lights, window switches. I believe the problem is in the interaction between the engine and interior harness.
 

hmn4389

New Member
The wire harness from the 5.0 based cars (95 and prior) is not compatible with the 4.6 based cars (97+).

I believe there are ways to make it work but its an excessive deal.
I switch the whole harness headlight to taillight when I swapped my 03gt motor into my 95 v6. (note) Door harnesses are different as well

I know alot of plugs are the same in terms of the actual plug in to the headlights, tail lights, window switches. I believe the problem is in the interaction between the engine and interior harness.
hmm interesting, so does that mean that if you put a 4.6 in my 2000, i shouldnt have to redo my interior wiring since the 2000 is 4.6 based?
 

JasonT1124

JasonT1124
I haven't posted on here in over a year. this is becuase i have been saving up and purchasing all necessary parts to do this swap. Its strange that i just came on here to search for this exact question.
In the past month, i have installed everything (mechanically) into the vehicle. The new motor is in, new radiator, new brake system, trans, driveshaft, exhaust, etc. Basically everything that is different between the cars.
I have replaced the harness from the engine to the computer (i.e. the one that runs down the right side fenderwell). The engine ignition system and harness and computer (both the engine and fenderwell harness) are from a 1996 gt. I can tell you this- everything plugs in just great and fine except everthing inside the car behind the right kick panel (where the computer is). I now have 3 plugs from the 96 v8 that wont fit into 3 plugs from 2000 v6. Also, 1 plug under the airfilter is not compatable.
There seems to be much more wiring in the 96 v8 harness then there is where it plugs into the 2000 v6 harness. I can see most of these wires are power distribution? possibly for underhood components?
Without that plugged in, I get power to almost everything inside the car. Please let me know if anyone has wiring diagrams for both the 2000 and the 1996. I need to get this wired asap.
 

bigdogcq

I paint the M's on M&M's
hmm interesting, so does that mean that if you put a 4.6 in my 2000, i shouldnt have to redo my interior wiring since the 2000 is 4.6 based?
That is true to my knowledge. There may be a difference between the pre 99 harnesses and the 99+ harness but I would be suprised.
Personally I would not swap in a NPI motor and if I had my choice I would put in a cobra motor over the gt (same amount of work).

I believe corral.net has alot of information on this kind of thing.
 

hmn4389

New Member
That is true to my knowledge. There may be a difference between the pre 99 harnesses and the 99+ harness but I would be suprised.
Personally I would not swap in a NPI motor and if I had my choice I would put in a cobra motor over the gt (same amount of work).

I believe corral.net has alot of information on this kind of thing.
thanks i wouldnt put in an npi motor, thats a load off though, i DEFINATELY wouldnt want to rewire the entire car.

I haven't posted on here in over a year. this is becuase i have been saving up and purchasing all necessary parts to do this swap. Its strange that i just came on here to search for this exact question.
In the past month, i have installed everything (mechanically) into the vehicle. The new motor is in, new radiator, new brake system, trans, driveshaft, exhaust, etc. Basically everything that is different between the cars.
I have replaced the harness from the engine to the computer (i.e. the one that runs down the right side fenderwell). The engine ignition system and harness and computer (both the engine and fenderwell harness) are from a 1996 gt. I can tell you this- everything plugs in just great and fine except everthing inside the car behind the right kick panel (where the computer is). I now have 3 plugs from the 96 v8 that wont fit into 3 plugs from 2000 v6. Also, 1 plug under the airfilter is not compatable.
There seems to be much more wiring in the 96 v8 harness then there is where it plugs into the 2000 v6 harness. I can see most of these wires are power distribution? possibly for underhood components?
Without that plugged in, I get power to almost everything inside the car. Please let me know if anyone has wiring diagrams for both the 2000 and the 1996. I need to get this wired asap.
thanks alot for your insight it really helps.
 

V6 swap

New Member
I haven't posted on here in over a year. this is becuase i have been saving up and purchasing all necessary parts to do this swap. Its strange that i just came on here to search for this exact question.
In the past month, i have installed everything (mechanically) into the vehicle. The new motor is in, new radiator, new brake system, trans, driveshaft, exhaust, etc. Basically everything that is different between the cars.
I have replaced the harness from the engine to the computer (i.e. the one that runs down the right side fenderwell). The engine ignition system and harness and computer (both the engine and fenderwell harness) are from a 1996 gt. I can tell you this- everything plugs in just great and fine except everthing inside the car behind the right kick panel (where the computer is). I now have 3 plugs from the 96 v8 that wont fit into 3 plugs from 2000 v6. Also, 1 plug under the airfilter is not compatable.
There seems to be much more wiring in the 96 v8 harness then there is where it plugs into the 2000 v6 harness. I can see most of these wires are power distribution? possibly for underhood components?
Without that plugged in, I get power to almost everything inside the car. Please let me know if anyone has wiring diagrams for both the 2000 and the 1996. I need to get this wired asap.
I'm doing the same swap as you what did you find out about the three plugs
 
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