Low electrical Power

[dadngt]

I've replaced the Negative cable, plugged into its stock locations Possitive cable same way. New Alternator in place tight & plugged in, new battery clamped down & ready to go. Checked everything making sure all wires are plugged in & all tools are removed. Started car, just to drive it to Autozone to have them figure out why its still low on power. The AMP light stayed on the whole time. They checked the alternator, the battery, & misc. cables. He told me that it may be in the fusable link that goes from the alternator to the battery. He said I can either bypass the fusable link or get a new one. Now for the life of me I don't know where the fusable link is for this part. He suggested it maybe under the battery tray & the wires run across the front of the car in the plastic wire covers. I disconnected the battery for now so it won't drain. What else should I be looking for?
1989 Mustang GT

 

[Glaze]

underdrive pullys installed?

stereo system?

I think hissin might have wiring diagram that he yanked off jriker for you to study and find the fusable links. Once you find fusable link you can measure for resistance from one end of wire to other end past link with voltmeter.

 

[Glaze]

try this link to autozone's wiring diagrams

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/19/59/5a/0900823d8019595a.jsp

Select this: Fig. 9: Wiring diagram, Body-1989-90 5.0L engine

I see 2 possible fusable links.

 

[dadngt]

thanks engines stock no pulleys, had a sub & amp but disconnected 3 years ago. I finally got the batt tray off to get a better look at the wiring thanks forthe links.

 

[jrichker]

The fuse links are in the wiring harness up next to the starter solenoid.


Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

 

[dadngt]

are the fusable links just the plugs with the clips I mostly break or would they have a fuse in them. I suck at electrical work

 

[HISSIN50]

are the fusable links just the plugs with the clips I mostly break or would they have a fuse in them. I suck at electrical work

As JRichker said, go to the solenoid's battery lug. See photograph, courtesy of Jrichker and Timewarped:

View attachment 429740

(original source here ).


Trace the wires down a little bit and you'll see where the links are. Check continuity on either side of the link. Also look for a rubbery feeling link, as this can indicate one which has burned.

Good luck.

 

[dadngt]

Well I'm throwing in the towel for tonight. Still trying to figure out how to read the wiring diagram. I'm not going to have any luck finding a bad wire with a test light when the batt. is sitting on the work bench am I? Anyways I'll give it a try tomarrow morning (already had to call in for work) so If its not done by arround noon I'm going to have to limp the car to a shop & let them handle it

 

[dadngt]

OK I didn't see HISSIN50 post til my last one popped up. I seen the links. so if one is rubbery then I just need to cut the link out & splice the wires together or get a new link? also Iwould feel better by having the link so how do the wires connect in them? Thanks for all the help things may be looking up tomarrow.

 

[HISSIN50]

You really should be able to find the correct fusible-link because of the wire colors for the alternator circuit. I check for continuity myself (the rubbery/gooey feel/look only helps me scan real quick for a link that stands out).

You absolutely MUST install a new link or some sort of circuit protection (a slow burn fuse would also work, as would a circuit breaker). Don't just splice the wires together or later you might be asking about how to fix fire damage.

I'm sure Jrichker and others can be more helpful.

Good luck.

 

[dadngt]

Ok I really didn't want to just splice the wires, So I'mnot going that way. I'm just about the run out & see what I can find. The wires from the alternator are black & orange so I'll look for those. Thanks

 

[dadngt]

At first look next to the battery In that mess of wires I found a connector with just2 black & white wires not plugged into anything, I'm also not seeing where it could have been plugged in at. So far the connectors look ok just everythings covered in dirt lol. Do I need to put the battery back in the car to run the test light?

 

[dadngt]

OK well its 3:13pm I went ahead & took the car to a shop at about 10:30 or so. Everything checked out fine except the brand new alternator so I went home took the new one off took it back to the store & they didn't have one instock but could get one tomarrow. Well I already missed a day of work because of this so I asked if a neighbor store had one. A store about an hour away had 1 in stock so I told him to have the store hold it for me. Well 2 hours later I have another alternator inplace. The first start I had low power again then I remembered I have to not only bolt in the alternator but also plug it in now I have the normal reading on the gauges now. Thanks for the help & I'll keep the wireing diagrams for future reference.

 

[HISSIN50]

So you got a bad initial-test at the parts store? That blows.

Speaking for myself (and Jrichker too, as I recall), I/we have both been given parts that didnt work right out of the box. I now make them bench/load test starters, alternators and batteries before I purchase them. E.g., I had my hands on 3 CS alternators for a Chevy truck before getting one that worked.

On the fusible links, you go by wire size (14 AWG/gauge, etc). If you find a fusible link that is the same color as the OEM wire, it's pure coincidence.

Anyhow, glad to hear you're up and running again.

 

[dadngt]

Thanks for alla the help. And I'll mark this lesson learned.