1998 s10e fan buffer

-- Beata Collection --


1998 S-10-E Electric Truck

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EV1 System 110 Inverter/Drive train

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I found the following modification in the buffer wiring harness for the radiator
cooling fan which indicates a failed fan buffer assembly.

The assembly's PNs =
(on wire = 711) - (on buffer =  27003265 717_) - ( on wire = 712)

Unfortunately this is a typical failure and the part is no longer available from
GM.  Therefore the only option is to de-epoxy the assembly, dianose its failure
and repair the original part.

The following are a few pictures of this projects progress.  More pictures to
follow  as progress is made.  2009.01

S10E

S10E Equilization Charge

S10E Fan Buffer

S10E 'A' Piller Gauges

S10E DTC-279

S10E DTC-104

S10E Library

This shows the unit as found after purchasing the S10E c2007

Note the lower right corner of the unit. It shows an unusual indentation which was later found to be the area of an over-temp failure event

Our initial attempt was to chip away at the epoxy base but we quickly learned that this would not yield acceptable results. We later came across a process to soften the epoxy and successfully cleared the PCB for repair. This process took nearly a week of soaking, removing material, and repeated sessions. Painful but necessary and eventually worth the results seen below.

Top view. Here is the basic board at the final stage of epoxy removal. In this picture the board is missing a number of parts that were removed for replacement

Bottom view

Although difficult to see, note the resistor scales added to this document

On reassembly and testing, we added a good sized aluminum heat sink & ceramic to the original design in hopes of saving it from the previous parts fate.