Trooper 94-changed alternator now have no lights and power

[Webraft]

The alternator in the issuzu trooper 94 was bad. I put a new one in. The battery is fully charged. Placed the key in the ignition and there is no light, no power of any sort. Same day, before I replaced the alternator, the door locks stopped working....I have the kind that you lock all doors with by placing the key inside the driver's door. I suspect the alarm system is shutting down the power altogether in the car. Or some of the fuses or sesnors that control the car power may have gone bad.

Like I mentioned, even my headlights don't work. I am no where near a dealer, could anyone suggest any solutions? I appreciation in advance.

JZ

[boritz]

It may sound obvious - but - have you reconnected the battery after replacing the alternator?

[EDIT] And are the other ends of the battery cables connected securely to their respective mounts? [END-EDIT]

If the battery IS connected - check the main (high Amperage) fuses.

[Webraft]

First, Thanks for you help.

Yes, the battery connected and wires look secure. I will check the fuse. Is there a way to check it? since it is a fuse that you can't readily see its faults.

JZ

[boritz]

The higher amperage fuses have a window in the top - look for either a continuous bright metal strip (good), or a broken strip (blown). You could also place a multimeter (if you have one) across a removed fuse to check for continuity.

Note, we are discussing the plastic box-shaped fuses with clear tops in the engine bay Relay and Fuse box. The fuses will be labelled on the lid of the box - there should be an 80A Main, a 50A Key Switch and a 30A ECM. I would first suspect the 80A Main. To remove a fuse, pull it straight up, off the two contact tangs. Don't confuse the fuses with the black relay boxes.

[EDIT 2 Nov 2007] My mistake, to remove the 80A Main and 50A Key Switch fuses, unscrew the retaining bolts [END-EDIT]

[Webraft]

Okay, the fuse is blown. I am on the way to get a new fuse. Any idea what caused the fuse to blow?

I disconnected the battery, before I replaced the alternator. I suppose there may be a bad ground somewhere?

I am going to pick up the fuse and install it and see if the car would start right up. I checked the battery with the meter and it is good.

thanks again

[boritz]

Originally Posted by Webraft

...fuse is blown...Any idea what caused the fuse to blow?...
I disconnected the battery, before I replaced the alternator...

Can only be blown by too much current.

Is the alternator (+) battery terminal and cable insulated correctly at the alternator end?

Originally Posted by Webraft

...I am going to pick up the fuse and install it and see if the car would start right up...

Be mentally prepared for the new fuse to blow if you haven't determined why the first one blew - buy more than one!

[Webraft]

I will recheck the connections and make sure that they are properly insulated.
************
Okay, I installed the new 80AMP fuse and as soon as I hooked up the battery, the fuse blew again. There must be a short somewhere causing the fuse to blow.
Any suggestions? I suppose there is a chance that the cable connected to the Alternator is making a connection to something else beside the Alternator. I am able to see the connection to the alternator from the opening behind the front tire, but it looks okay.
I really never had the old alternator checked at the shop, it just tested negative while it was still on the car. May be there is another element that is causing the mess?
Thanks in advance for your assistance. I feel like I am close to solving the puzzle.

[boritz]

Yes, there must be a short to permit more than 80 amps to flow.

Try disconnecting the battery (-) ground and search for continuity with a multimeter, between the battery (+) positive and a body ground point. Disconnect the alternator (+) wire to test if the short is going through the alternator.

[Webraft]

Okay, on the first test, how do I do that? Do I use the meter between the battery + pole and the body ground point? is that just any point on the body? IF there is continuity, then I suppose my Alternator connection is not insolated?

I will follow up as you suggested.....sounds very reasonable.....thanks,

[boritz]

Yes, you're on the right track. Any decent ground points on the body or engine.

I forgot to explain that, after disconnecting the battery (-), put in a good 80A main fuse, since your test circuit will need to pass through it.

Remove the fuse if you reconnect the battery (-) without finding the short, or it will blow.

What you are trying to find is the short-circuit path for current to flow from the battery (+) to the ground point and back to the battery. You will need to disconnect any connection which is in a suspected short-circuit path to test if it is the culprit.

I assume that your lights were working before you removed the alternator?

Because you have been working on the alternator and it's connections, these are the prime suspects for the short-circuit.

[Webraft]

Great directgions....thanks again.

As strange as it may sound, I am having trouble finding any nearby store that carries the 80 amp fuse. Will look else where tomorrow.

[Webraft]

I reached on top of the Alternator and loosened the nut to release the cable; I turned the contact around so that it had no chance to come in contact with anything else. I placed the nut back on and made it tight. I then pulled the insualting boot on top of it. The other connection to the Alternator looked good and appears to have and no malfunction.

(I have a good fuse inplace) I have the battery + pole connected and - pole hanging loose. I used the meter with the red probe touching the + battery and the black probe touching the engine body or the car body, I get continuity.

Does this mean I have a short in my Alernator cable?

[boritz]

Originally Posted by Webraft

...Does this mean I have a short in my Alernator cable?

Very possibly; or worse, a short inside the alternator.

Disconnect the cable at the alternator and ensure that the cable end is isolated from the body/engine.

Repeat the test from the battery (+) pole to a ground point - if there is continuity there must be a fault along the cable.

If not, test from the alternator (+) connector to a ground point or the alternator body - if there is continuity there must be a fault in the alternator. Check the plastic insulating pedestal on the alternator (+) connector to ensure that the bolt is not contacting the alternator cover or body.

[Webraft]

have been swamped with work and other Misc. stuff....hope to get to work on the car tomorrow AM.

[boritz]

Hope that you will beat it soon.

Just correcting myself: you have obviously discovered by now that I erroneously said above that the 80A Main can be pulled out - it can't - you have to remove 2 screws.