1989 GMC V3500 Square Body Wont Crank after New Battery Installed

[jrc]

My 89 GMC V3500 needed a new battery so I replaced it yesterday. It ran fine yesterday and today, but I noticed when trying to crank it a couple of times it would just click like the battery was dead, but would crank if I tried again right after. Then it just quit turning over at all. Nothing.

Tested the battery and connections good and corrosion free. Checked the fuses under the dash and they are good.

Strange thing is the interior light works when I open the door, and the headlights will work, but the radio clock dosent display when I turn on the ignition. It will light up however if I push the power knob to have it display the time. I dont hear any click or anything now when I turn the key. Also, with the key turned on, I checked the AC fan to see if the blower would run, and it doesnt.

I'm at a loss. Please help, anyone.

Thanks

 

[perolli]

Seems like a bad ground. Check to see if the negative battery cable is tight, at both ends. Used to happen to me in my old jeep, the nut was stripped, I would just have to wiggle the terminal and it would start right up.

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[PrairieDrifter]

If you can move the connectors on the terminals at all, even a tiny bit then they aren't tight enough. Don't be gentle trying to wiggle them too, after driving they can wiggle enough to move so it wont start the next time acting like it has a dead battery. It would be a good idea to clean up the connections for the cables too. On the frame and on the starter.

Make sure your alternator is working properly and charging the battery at about 14v, a little higher.

 

[chengny]

There are two primary power feeds into the cab. These two (red) leads originate at the "B" terminal on the starter solenoid. They immediately split apart and then are run separately through the firewall and into the cab.

There is a fusible link in both leads at the beginning of the run - the links are located within a couple of inches of the solenoid "B" terminal. Somewhere in the area indicated:

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One of the main power leads takes a straight shot to the firewall. The other runs through the firewall junction block. See the yellow markings - disregard the red:

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The JB is used as a convenient place to splice wiring that connects to various engine compartment components. Immediately after leaving the JB, the power feed to the cabin has an additional fusible link. This link is within a few inches of the block.

Now I'll get to the point:

All the components you list above that do not work are supplied with power on the lead that passes through the junction block - the one with the extra fusible link.

All the other components (the ones that do work) are fed by the primary power lead that by-passes the JB. These include the parking/head lighting circuits, the courtesy and dome lighting and also the power to the clock in the radio. The horn is also on that circuit - I bet it still works.

The exterior lighting feed splits off inside the cab and goes straight to the H/L switch. The other side of the split feeds the far left column of the fuse block and the two column of sockets up near the top of the fuse block. If you check the dwg of the fuse block below, you will see everything that works is on the left hand side:

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So you need to check the applicable fusible link at the solenoid, the terminals on the junction block and the fusible link on the outlet side of the JB. Although fusible links are designed to fail completely - and only when subjected to excessive current flow - they do sometimes just mechanically break inside and will not show anything wrong.




In addition to all the possible points to check listed above, there is another component that must be considered - the ignition switch.

Not all, but many of the circuits fed by the power lead that goes through the junction block are also ignition switched. After leaving the switch they run down to the line side of the fuse block.

I would break out the VOM and just start at the beginning. Check for voltage loss after the lower fusible link, the JB terminals, and the link between the JB and the firewall. Shake/wiggle the leads as you check voltage and observe any sudden drops.

 

[jrc]

Working

So, whomever had the truck before removed the fusible link. Turned out the problem was a not sufficient contact on the battery terminal with that wire.

I do want to install an inline fuse, so what size should I go with and fast or slow blow?

Thanks for the help.

 

[chengny]

Which link are you replacing?

Fusible links are rated by wire gauge not current capacity - and should really only be replaced with a new fusible link. They are not hard to find. The one at the junction block is spec'd at 16 gauge wire.

http://m.napaonline.com/parts/PartsD...694_0452802200

Just get a new link and solder it in where the factory link was (use heat shrink tubing at the solder joints).


Some fun facts about fusible links:

The fusible link is actually the short length of wire on the supply side of the plastic connector (the hard plastic cover with the amperage rating of the link embossed on it).

Here is a bit more detail on fusible links:

In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit.

Not all fusible link open circuits can be detected by observation. A blown link often, but not always, has "bubbly" appearing insulation making troubleshooting easier. Always inspect that there is battery voltage past the fusible link to verify continuity.

Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes (wire gauges), each fusible link is four wire gauge sizes smaller than the wire it is designed to protect. For example: to protect a 10 gauge wire, use a 14 gauge link (or for metric, to protect a 5mm wire, use a 2mm link). Links are marked on the insulation with wire-gauge size because the heavy insulation makes the link appear to be a heavier gauge than it actually is. The same wire size fusible link must be used when replacing a blown fusible link.

Good and damaged fusible links:

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To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip the wire and use staking-type pliers to crimp the splice securely in two places.

Choose the shortest length that is available. A fusible link should NEVER be longer than nine inches. Fusible links longer than this will not provide sufficient overload protection.


To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each wire harness.



Double wire feed fusible link repair:

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[jrc]

Still Trouble...

Well, I thought I had it fixed. I drove it and it died. I popped the hood, wiggled the wire (bigger one at the junction block that doesnt seem to be a fusible link), and got it started back.

Replaced the fusible link, but the old tested ok with continuity. Cleaned the ground on the chassis and alternator along with the junction block studs, connectors, and nuts. As soon as I turned the switch to start, I heard a click, then the clock went off. Dome light, horn, and headlights will work like before.

Tested that fusible link and tested ok.

Back at square one...

Suggestions?

 

[perolli]

Have you checked the wire itself? Seems like you have tried most other things. Could be it has burned up under the sheathing and not conducting well.

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[jrc]

Fixed!!

So, my problem was the wire from the battery to the starter. Where the wire connects to the starter, it was corroded and burnt from shorting or poor connection. Took it completely off and scraped the contact points. Put it back on and all is great.

Now I was presented with a tranny issue where it wont go into 2nd, 3rd, or reverse. Posted that earlier.

Thanks for everyones input.