2003_Acura_MDX_Rear_AC_Thermal_Cutoff-20110918

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The kids were complaining that the 2003 Acura MDX's rear A/C fan was no longer working. Google found the following information:

x03-048e revised.pdf: Honda Service Bulletin 03-048, March 2004. Applies To: 2003 Pilot EX. . . . Replace transistor assembly P/N 79330-S2K-941 with a new P/N 79330-S3V-A51. The pictures match my vehicle. The prices Google was returning made me continue searching for a cheaper fix.
http://www.mdxers.org/forums/14-problems/29595-1st-gen-mdx-front-ac-fix.html: This thread is for the first generation Acura MDX front A/C transistor assembly. It specifies Panasonic EYP-2BN109 THERMAL CUTOFF 114C 2A/250VAC. This did not match my rear A/C transistor assembly problem.
http://www.mdxers.org/forums/14-problems/17346-broken-rear-ac-grrr.html: This thread also says that inside the transistor assembly is a thermal cut off which is the specific part which failed.

mp29a4 called out the following part: "The Digikey part no. is P10920-ND, made by Panasonic, whose mfg. part no. is EYP-2BN109. Decription: Thermal Cutoff 114C 2A/250VAC." I found this to be wrong for my transistor assembly. I recommend you replace what you have in your transistor assembly.

I started by purchasing something close to 114C 2A at MarVac Electronics: NTE8115 Thermal Cut-Off 117C 15A. Once I opened the transistor assembly, I found the original thermal cutoff was actually 133C 2A N126. I also verified the original thermal cutoff really was open using a continuity test.

The NTE8115 cutoff temperature was too low. The next up that MarVac had in stock was NTE8125 128C 15A or a NTE 8139 141C 15A. It turns out the 15A part has a very large cylinder. It will not fit the narrow channel in the transistor assembly. I was going to have to order the exact part online.

EYP-2BN126 is discontinued. It has been replaced by EYP2BN127. I ordered 5 at $1.24 each from Mouser Electronics. The total came out to $11.40.

The original thermal cutoff has some black insulation on the wire leads. I had to pull really hard to get them off then slipped them over the new wire leads. I trimmed the wire leads to match the original lengths.

AFA0000CE1.pdf last page, Table-1 Soldering Conditions states, "Temperature of Soldering: 300 °C Time: 3 ". I recommend using a continuity tester on the part before and after soldering.

Vacuum the fan filter, install the transistor assembly, turn the key, and the rear A/C fan is working again! Replace the driver's side panel, clean up, and mark the calender to clean the filter again in a year.

Odometer reading: 56,631 miles.