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How to Test Fusible Links

Hi,

I want to test the fusible links at the starter and at the battery. My 88 TransAm GTA died on me suddenly, and only a few electricals are working now, and many people think it's a fusible link which has blown. I have a voltmeter. My plan is to disconnect the wires attaching to the starter, and touch the positive lead from the tester to each wire, and the neg lead to a ground, and see if there is voltage with key on, key off, and in "start" position, for each wire.

Is this a safe way to test the fusible links? I don't want to cut any wires if I can avoid it. The links at the starter are just one inch long rubber things, and seem to be builtin to the wire, no place to disconnect / replace them other than cutting them out.

Thanks

Reply to
Lecher9000
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That inch long thing is just a waterproof crimp connector, the 6- 8" of wire from there to the loop end on the solenoid is the 'fuse link wire'.

The only way to test them easy is to have a sharp probe on the meter and dig into the wire on the harness side of the black tube crimp connector.

Then you can turn the key to run and ground the other meter probe to see if you have 12 volts or you can just do a continuity check with ohms from the same place on the harness side of the connector to the starter solenoid bolt where the loop connector connects.

I usually put a dab of silicone in the hole I punched when pinning the wire to make it sealed again.

'Most' of the time, a meter isn't needed. If you just bend and pull on the wire, usually a burned through one is easy to spot if the insulation isn't actually burned so it is an instant spot.

You can buy fuse link wire by the foot. Keep it the same length as the one you are replacing and most important get the same gauge of wire.

On my 86 Jeep that has GM wiring in it, the lights, ignition and alternator circuits use 14 ga fuse links to protect the 10 ga harness, same for a GM car I fixed recently.

You have to use crimp connectors, you can't solder fuse link wire without damaging it I have been told.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Lecher9000 wrote:

Reply to
Mike Romain

Do not solder fusible links - should say so on the package - 550 degrees C (solder melt temp) is too much heat - will cause link to go.

Andrew

Mike Roma>That inch long thing is just a waterproof crimp connector, the 6- 8" of

Reply to
Andrew Paule

Radio Shack and all our local automotive supply houses now sell crimp connectors or butt connectors with a heat shrink covering on them. Crimp and heat and it is weather tight. They also sell heat shrink tubing in 4" chunks you can slip on first to slide down and cover it after.

Good call on the FL wire gauge. If it says 16 on it, then it is likely protecting a 12 ga. harness.

Look at the other ones. 'Usually' on a GM, the largest wires are the headlights and the alternator wires. They are usually 10 ga. If so a

14 ga. FL protects them. (2 gauges off)

Compare the biggest wires with the one you are repairing. My guess is the burned one will be slightly smaller than the others.

Or you could just snip a 1/2" off it and take it in to be sized. I use a wire stripper to take an educated guess on the wire size. If I use the 12 ga hole for stripping and it takes strands of copper with it, the wire is bigger or at least 10 ga. If it won't strip or leaves strings of plastic behind, then it is likely 14 ga wire.

And yes, the dealer is likely the easiest place to get bulk fuse link wire.

Mike

Lecher9000 wrote:

Reply to
Mike Romain

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