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Tuesday, September 02, 2014

Doug's Domain

Doug Vetter, ATP/CFI

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Saturday, June 07, 2008

Aux Fan Connectors Replaced

A couple days after I "repaired" the aux fan's electrical connection I noticed, once again, that the aux fan would not run with the air conditioning turned on. Knowing full well that much warmer weather was forecast for later in the week and the aux fan would be called provide airflow through the coolant radiator as well as the condenser I decided to fix the problem by replacing the faulty connectors. The problem was identifying the type of replacement connector assembly appropriate for the application.

(Image: Original auxiliary fan electrical connectors detached)The primary criteria was current capacity. The aux fan is connected via 14 gauge stranded wire. In 110V AC circuits that's good for about 15 amps, but in 12V DC circuits the same wire size is rated for anywhere from 30-40 amps depending on the length of the wire. This is consistent with the 30 amp fuse used in the aux fan circuit. Further complicating the solution was the need for a sealed connector. The front of the car is regularly battered with water with the addition of salt spray in the winter. Salt and water are enemies of any good electrical connection so I considered a sealed connector essential to the solution.

In my search I stumbled on several connector types including Weatherpak (commonly used on GM products and good for 20 amps), Metri-Pak 280 (good for 30 amps) and Deutsche DTP connectors (25 amp). I gravitated toward the Deutsche connectors primarily because I found they were optionally available with solid contacts rather than the cheaper die stamped equivalents.

The problem? Not only are the Deutche connectors about twice the price of the Weatherpak units (sold as kits including the connector shells and contacts, the plug and receptacle are each about $14), the crimping tools for the solid terminals are ridiculously priced at $300 or more. I managed to find one for $150, but that was still out of the question because I would likely never use it more than once. I asked one supplier advertisting custom fabrication if they would build a connector assembly for me with pigtails so I could splice the assembly into the wiring and avoid the tool purchase. The quote for the completed assembly came in at $72. Expensive for a single connector, but far more reasonable than the nearly $200 I'd pay for the tool and the necessary components.

Unfortunately, by the time I'd gathered this information it was late in the week and I had to use the car in 95+ degree heat today so I managed to splice in some simple crimp-on male/female terminals I had in my spare parts bin. I took a few pictures of the wiring before I cut off the connectors and then reassembled the connectors and checked continuity to make sure the connector was wired as I expected. The resulting fix isn't particularly pretty looking, and even with some electrical tape tightly wrapped around the terminals I would hardly consider the connections sealed, but it should be satisfactory for now.

Later that evening I went to my brother's engagement party at a winery in town. After I pulled into the parking lot I opened the door and walked around to the front of the car to find the fan running as expected. I then reached back into the car and turned off the air conditioning. This time the fan continued to run, no doubt due to the fact that the coolant temperature had exceeded the low-speed theshold as I drove around slowly with little air flowing over the radiator looking for the place. I shut the engine down at that point confident that I'd fixed the problem, but I resolved to replace the terminals with a proper sealed connector as soon as my schedule permits.

Mileage: 161150