P0526 Cooling fan speed sensor circuit — TSB

Fix code P0526 Cooling fan speed sensor circuit

GM has issued a service bulletin to address a P0526 Cooling fan speed sensor circuit trouble code on the following vehicles:

2002-04 Olds Bravadas

2002-05 Chevy TrailBlazers & TrailBlazer EXTs, GMC Envoys & Envoy XLs

2004-05 Buick Rainiers and GMC Envoy XUVs

2005 GMC Envoy Denalis & Envoy XL Denalis

The P0526 Cooling fan speed sensor circuit problem appears because of damaged wires in the cooling fan harness. The damage occurs because the harness pulls out of its plastic protective sleeve, exposing the insulation to the sharp edges of the sleeve. Replace the harness with an improved design (Part No. 89024920) and tape the wires to prevent movement within the sleeve. That’ll solve the problem. Here’s how to do it.

1)     Remove the cooling fan assembly and place it on a workbench.

2)     Disconnect the connector from the fan clutch and remove the harness from the plastic sleeve while feeding the wires out of the slot.

3) Wrap the area of the wires that will go into the sleeve with electrical tape. Make sure the tape is positioned at least 1 in. from the connector so the wires can be fed completely into the slot in the sleeve.

4) Next, push the wires through the slot and install the harness completely into the plastic sleeve. To complete the fix, reconnect the fan clutch electrical connector, install the fan assembly, clear the DTC and check for proper fan operation.
©, 2013 Rick Muscoplat