Cox Abele
10+ Year Contributor
- 485
- 53
- Jul 4, 2010
-
Roanoke,
Virginia
This post is more for the sake of putting all of the random threads in one place for a concise answer. I am in the middle of swapping my 98 harness for a 95. The differences are small, but troublesome if you think it is just plug and play.
1.) 95-96 has a single relay for the fuel pump and mpfi. This relay is mounted on the passengers side of the center console, just below the radio. It is secured by 2 10mm bolts. The 97+ harness has two separate connectors for two separate relays. The relays can not be exchanged between the two harnesses, so be sure to get the one specific to your harness.
2.) The evap/purge setup between the two harnesses is entirely different. On the 95-96, there will be a 2-pin connector and purge solenoid mounted on the firewall next to the egr solenoid. On a 97+ harness, there will be a 5-pin connector located under the drivers seat on the same branch as the rear o2 sensor. On the 97+ harness, it'll dive back into a body harness that runs the length of the driver's door, extending to the purge solenoid and differential pressure switch mounted on the fuel tank. Depending on your setup, if you are swapping just the engine harness, you'll need to eliminate the readiness check and trouble code in link of ecuflash.
3.) The wiper motor connectors will need extended. On the 95-96 harness, the connection is made at the firewall. On the 97+ harness, the connection is made under the wiper cowl. Because I had a parts car, I was able to pull the entire motor and linkage assembly and swap it over, negating my need to extend these wires. It was easier and far cleaner or an install.
4.) If you have the factory security system, the 95-96 harness carries a different connector for the second horn that is located behind the battery. Obviously, this is not absolutely necessary, but it's nice to not disable a factory option because of laziness.
5.) You will have an additional plug on the 95-96 harness located next to the fuel pump and 1/2 tac signal connectors which are located on the firewall by the battery/throttle cable cluster. This plug is brown, single pinned and will have a cap over it. This plug is used to ground while adjusting ignition timing. It has no function in car running a 97+ CAS due to it's lack of adjustability. Leave it capped.
6.) The CAS plug is obviously different between the two. The 95-96 CAS is located under the intake cam gear on the driver's side while the 97+ CAS is off the back of the intake cam on the passenger's side, much like a 1g. Depending upon which ECU and CAS combo you run, you'll need to do some spark plug wire swapping as well as pin swapping at the ECU for the injectors. While you may need to swap CAS plugs, the year of the harness is not important; you should be more concerned over the ECU/CAS combo rather than the connector. It goes a little something like this:
Swap: Yes/No
95-96 ecu w/ 95-96 CAS: No
95-96 ecu w/ 97+ CAS: Yes
97+ ECU w/ 97+ CAS: No
97+ ECU w/ 95-96 CAS: Yes
This is a the 2g plug wire swap for a '95-'96 ECU with a '97-'99 CAS OR a '97-'99 ECU with a '95-'96 CAS.
As for the injectors, you'll swap pins 1 and 14, pins 2 and 15. Schematics below:
95:
99:
1.) 95-96 has a single relay for the fuel pump and mpfi. This relay is mounted on the passengers side of the center console, just below the radio. It is secured by 2 10mm bolts. The 97+ harness has two separate connectors for two separate relays. The relays can not be exchanged between the two harnesses, so be sure to get the one specific to your harness.
2.) The evap/purge setup between the two harnesses is entirely different. On the 95-96, there will be a 2-pin connector and purge solenoid mounted on the firewall next to the egr solenoid. On a 97+ harness, there will be a 5-pin connector located under the drivers seat on the same branch as the rear o2 sensor. On the 97+ harness, it'll dive back into a body harness that runs the length of the driver's door, extending to the purge solenoid and differential pressure switch mounted on the fuel tank. Depending on your setup, if you are swapping just the engine harness, you'll need to eliminate the readiness check and trouble code in link of ecuflash.
3.) The wiper motor connectors will need extended. On the 95-96 harness, the connection is made at the firewall. On the 97+ harness, the connection is made under the wiper cowl. Because I had a parts car, I was able to pull the entire motor and linkage assembly and swap it over, negating my need to extend these wires. It was easier and far cleaner or an install.
4.) If you have the factory security system, the 95-96 harness carries a different connector for the second horn that is located behind the battery. Obviously, this is not absolutely necessary, but it's nice to not disable a factory option because of laziness.
5.) You will have an additional plug on the 95-96 harness located next to the fuel pump and 1/2 tac signal connectors which are located on the firewall by the battery/throttle cable cluster. This plug is brown, single pinned and will have a cap over it. This plug is used to ground while adjusting ignition timing. It has no function in car running a 97+ CAS due to it's lack of adjustability. Leave it capped.
6.) The CAS plug is obviously different between the two. The 95-96 CAS is located under the intake cam gear on the driver's side while the 97+ CAS is off the back of the intake cam on the passenger's side, much like a 1g. Depending upon which ECU and CAS combo you run, you'll need to do some spark plug wire swapping as well as pin swapping at the ECU for the injectors. While you may need to swap CAS plugs, the year of the harness is not important; you should be more concerned over the ECU/CAS combo rather than the connector. It goes a little something like this:
Swap: Yes/No
95-96 ecu w/ 95-96 CAS: No
95-96 ecu w/ 97+ CAS: Yes
97+ ECU w/ 97+ CAS: No
97+ ECU w/ 95-96 CAS: Yes
This is a the 2g plug wire swap for a '95-'96 ECU with a '97-'99 CAS OR a '97-'99 ECU with a '95-'96 CAS.
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As for the injectors, you'll swap pins 1 and 14, pins 2 and 15. Schematics below:
95:
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99:
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