Replacing alternator to battery "connector"

[Paul Meyers]

This post is designed to supplement the Mike Larosa post of July 1999 about
replacing a corroded connector between battery and alternator. The symptoms
are failure to charge a tested good battery with a tested good alternator
and evident heat damage to the area of the connector (under the carpet up
against the passenger side firewall - bundled with a bunch of other stuff,
including the boost sensor hose between ECU and intake manifold). 

The connector itself is made of what looks like brass, is about 75 mm long
and roughly 15 mm in diameter. Evidently, the two wires were inserted into
the connector and mechanically swaged together. The wire coming from the
alternator has much finer strands than the wire coming from the battery,
though they are roughly the same diameter. The insulation on mine had
degraded so much that it came easily came off in chunks, revealing
thoroughly corroded stranded copper wire on sides of the connector. One
wonders what the engineers could have been thinking. This is not a good
design for long-term use.

First, disconnect the battery. Remove the glove compartment and underdash
trim on the passenger side. Remove the ECU cover, so you can released the
carpet wedged behind it.
Release or clip the tie holding the big bundle of wires and stuff to the
footwell firewall. Free the big cable from the other wires and such in the
bundle. Remove all the loose insulation you can from the area of the
connector. You're now ready to begin removing and replacing the splice.

Rather than cut out the connector as Mike did, shortening the cable by
roughly 100 mm, I determined to save as much of the wire as possible by
removing the connector without cutting the wire. If you have a lot of tools,
sometimes you can use them to advantage.

Using an air powered micro die grinder (sort of like a slightly larger
version of your dentist's drill) mounted with a diamond coated disk (roughly
25 mm in diameter), I cut two slots in the connector along its length on
opposite sides. The die grinder cost me about $40 at Harbor Freight Tools.
The disk was about $5, along with some other diamond coated cutters. Of
course, I already had the air compressor.

The slots were approximately 3 mm deep, the thickness of the connector
itself. This cut the connector into two halves. It turns out that the wires
weren't butted, but had about a 10 mm gap at the center of the connector. I
inserted a screw driver into the gap and rather easily pried the two halves
apart. With a little more effort, I removed the connector halves from the
wire without breaking so much as a strand.

I cleaned the copper wires with rust remover and mechanical abrasion (sand
paper), rinsed them with water and coated them with anti-oxidant grease (GB
Ox-gard, Home Depot electrical section, $4). 

Next I inserted about a 150 mm length of exterior grade shrink wrap (big,
thick stuff used for splicing buried electrical cables with 240 volts
flowing through them: Ideal Direct Burial Splice Kit; also available in
Canada and the UK; cost $9 at Home Depot) onto the battery end, since there
is a longer length of cable on that side. 

I then inserted the greased cable ends into a new splicer/connector. This
one uses screws to provide mechanical clamping on each end to be spliced.
The splicer I used was designed for wire up to #1/0, exactly the size needed
for the wire at hand (Ilsco brand, SPA-0-1B, made by Adamax, Inc., $4 Home
Depot). I screwed down the screws creating a sturdy, resilient connection.
Before sliding the shrink wrap over the splice, reconnect the battery and
start the engine. Using a DVM, test the voltage drop across the splice. Mine
registered .06 Volts, plenty acceptable in a 13.7 volt system.

Slide the shrink wrap over the splice, making sure to roughly center the
spice in the shrink wrap. Use a heat gun to shrink the wrap. Paint each end
of the shrunk wrap with liquid electrical tape to seal the ends, providing
an nice, watertight seal on the ends. 

Replace the carpet, ECU cover, etc. and you're back on the road.


Paul Meyers
Gray 87 5KCSTQ 1.8bar eurolights fuchs 147 kM gulp! cooked loom
Pearl 88 5KCSTQ 1.8bar eurolights fuchs bilsteins 122 kM 2pc-em k24 turbo
Metallic White 87 5KCSTQW 192 kM, daily driver w/respliced battery wire
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