Having problems with your 2003 Mercury Grand Marquis ?
Where is the computer located/ - 2003 Mercury Grand Marquis
You have to disengage the PCM (computer) wiring harness from the PCM as the PCM is removed from under the dash. The PCM connector is located on the firewall under the hood to the left of the brake booster, you'll see the a large retangular wiring connector (120 wires) with a single bolt in the middle. Unscrew the bolt, go back under the dash to remove the PCM.
Repair Help & Product Troubleshooting for 2003 Mercury Grand Marquis
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