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The air conditioning system on some 1997-99 Jeep Cherokee and Wrangler models may work fine for the first few minutes of operation, then lose its ability to cool the interior.

Chrysler Group L.L.C. said the system will then often return to normal after the vehicle is allowed to sit for a while, only to lose its ability to cool once again under high system demand.

The car maker attributed the problem to a frozen evaporator, caused by an out-of-spec low pressure cycling switch. Installing a new-design, better quality cycling switch should eliminate the A/C woes.

Order part No. 05015871AA for 1997 models; part No. 05015872AA for 1998-99 models.


Some 2007 Ford Edge and Lincoln MKX models may turn on the check engine light and store trouble code P0451 in the PCM.

If the trouble tree for the code leads you nowhere, the problem is most likely due to electromagnetic interference acting on the fuel tank pressure sensor circuit, according to Ford Motor Co.

Installing a new capacitor/-jumper harness, part No. 7T4Z-18801-C, into the circuit should eliminate the interference and turn off the check engine light.

Detailed installation instructions are included with the harness.


Some 2006-07 General Motors Co. vehicles with 3.5-liter and 3.9-liter engines may produce a small coolant leak from the upper portion of the engine.

One likely source of the leak, according to GM, is a worn gasket between the coolant crossover pipe and the rear of the right-side cylinder head. Installing new-design service gaskets (part No. 12577704 and part No. 12590668) at both ends of the crossover pipe should stop the coolant loss and eliminate further leakage issues.

GM vehicles that are prone to the problem are Buick Terrazas, Chevy Impalas, Malibus, Monte Carlos and Uplanders and Pontiac G6s and Montana SV6s.


Drivers of 2004-07 Sportage models may come into your shop with a complaint that the vehicle is difficult to start or won't start at all when the overnight temperature falls below freezing.

One probable cause for the difficulties, Kia reported, is a restricted exhaust. Ice accumulation in the muffler/pipe assembly is the usual source of the restriction. Drilling a small hole into the pipe to allow condensation to escape should eliminate the no-start complaints.

Begin the job by putting the vehicle on a lift. Now remove the muffler/pipe retaining nuts, followed by the muffler and pipe. Look inside the pipe by the flange. If you see ice, remove it prior to drilling the pipe. Next, get a 3mm drill bit and chuck it into your drill.

Turn over the muffler/pipe assembly so the bottom side of the pipe is facing up. Now measure about 8 inches inside of the flange and drill the drain hole. To complete the repair, reinstall the muffler/pipe, tighten the retaining nuts to 40 ft-lbs and lower the vehicle.

“Factory Fixes” is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. He can be reached via e-mail at For more Factory Fixes, go to and click on the Service Zone icon. This column first appeared in Service Zone.

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