Chapter 22 – Front seat warmer rewire

Today was another heavy research day… I keep having new information serendipitously presented to me via FaceBook, etc. ….  then I ask a question, discussions ensue, and I find myself trying to finalize various configurations on my build (not bad, but often not my intent).  Today it was specifically regarding firewall cable pass-thrus.  Yesterday it was information that Chris Randall shared on FB about wiring up the EIS4000.  I’m grateful for the information to be certain, but these little heading changes do eat up some time.

I finally got to the actual build early this evening.  All told I spent well over 4 hours rewiring the front seat warmer system with Tefzel wire vs the automotive wire it came with. There were a few places I didn’t swap out the wiring since the amount of wire that would have been removed (relay jack jumpers) or the configuration just wasn’t worth the effort.  So, all in all I’d say I ended removing and replacing about 70% of the automotive wiring with the Tefzel.  Not bad.  And, in the process reduced the wiring harness weight by over 2 oz. Nothing to shout from the rooftops of course, but at least I didn’t ADD weight!

I started out by focusing on the front seat warmer switch rewiring.  I did replace the PIDG Fast-ON terminals on the switch since I wanted the higher grade Fast-ONs, plus it was just easier and faster.  Moreover, I’m getting critically low on my fine wire solder (the good stuff!).

Here’s the front seat warmer switch after I rewired it with Tefzel wire and new terminals.

For the connector that goes on the end of the switch’s 4-wire harness, I chose to go with a 4-position Mini-Molex connector.  As I mention often, I’m not a huge fan of Molex, but this fits the bill for a lightweight, easily built connector on a non-critical component.

I finished the front seat warmer switch conversion, including the attachment of the Mini-Molex connector, and then I knocked out the GIB seat warmer switch conversion as well. The wire bundle on the far right is one of the original switch wiring harnesses.

Here’s how the front seat warmer assembly looks (minus the switch harness) as it comes from the factory.

Here I’ve removed a couple of the larger unneeded sub-harnesses, and am working on the main lead wire bundles to the two separate heating pads (seat bottom and seat back).

Here’s a closer shot of the main area of the wiring harness.  The white connector in the upper left corner will attach to the relay that is already mounted in the fuselage.  The two connectors in the lower right attach to the actual seat warming pads.

I then rewired the front seat warmer harness with Tefzel wiring.  Since the Fast-ON connectors in the relay jack have locking tabs, I figured it would just be easier to cut away nearly all the automotive wire and solder in almost completely new segments of Tefzel wire.

I then soldered the power wire to the Fast-ON tab.

And then covered it with heat shrink.

Here’s the new & improved front seat warmer setup with the majority of the wiring swapped out for the much more robust and safer Tefzel wiring.  Again, it also reduced the overall weight by a couple of ounces…. not bad.

I didn’t realize I was so low on solder until I nearly ran out this evening. I’ll order some more solder in the next day or so, but that will help facilitate my transition back into shop mode.


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