AN EMB145 AWAITING TKOF CLRNC GOT A #1 INST COOLING FAN WARNING. RETURNED TO THE GATE. FOUND COOLING FAN INSTALLED INCORRECTLY.

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IN REF TO THIS ACFT CAME IN WITH #1 AHRS OVERHEAT MESSAGE. DISCOVER THAT THE AHRS #1 FAN WAS INSTALLED BACKWARDS WITH THE ARROW POINTING UP. CLOSER INSPECTION OF THE ACFT MAINT LOG DISCOVERED THAT I INSTALLED THE FAN. ACFT CAME IN WITH FO'S PITCH TRIM SWITCH INOP. WHILE INSTALLING THE FO'S PITCH TRIM SWITCH WE NOTICED THAT EICAS SHOW #1 AHR OVERHEAT. I WAS WORKING WITH MR X. HE WENT TO GET THE AHC'S FAN AND HELP ME TO LOOSEN THE #1 FAN AND DISCONNECTED 1 WIRE (THE BLACK WIRE). HE COULD NOT DISCONNECT THE RED WIRE DUE TO DIFFICULTY WITH AN INJURED L ARM. I PROCEEDED TO INSTALL THE #AHC FAN; FIRST CONNECTING THE BLACK WIRE TO THE ONLY PLACE I COULD CONNECTED AND THEN DISCONNECT THE RED WIRE FROM THE OLD FAN AND CONNECTING THE RED WIRE FROM THE NEW FAN. I INSTALLED THE FAN IN ACCORDANCE WITH 34-21-03. PRINTED THE INSTRUCTIONS FOR THE INSTALLATION. STEP I(1) AND J(2) IN MY PERCEPTION THE AIRFLOW ARROW ON THE FAN WAS POINTING DOWN AS WELL AS THE AIRFLOW. ACFT FLEW FOR 10 DAYS WITHOUT A #1 AHC OVERHEAT DISCREPANCY. THE CORRECTIVE ACTION FOR THE REPAIRED OF #1 AHC OVERHEAT FOR ACFT WAS TO PUT AHRS #1 FAN WIRES IN CORRECT ORDER.