I've got a few ongoing threads across the forums but I'm trying to cast a wide net as far as getting fellow owner input and experience (and shamelessly plugging my youtube channel). I picked up a 1988 Mustang GT in late January. I've wanted a fox body for a looooong time. The first Mustang I ever rode in was a fox body. The first Mustang I ever drove was a fox body. I’ve been a huge fan of these cars since I was a teenager and always wanted to own one. I also wanted a project car that I could tinker with and build up and mod and learn on. I've been making time for that experience whenever I have had free weekends over the past two months. I've been partially documenting my progress through videos on my YouTube channel and I am always open to suggestions either through these types of threads or through comments on the videos. Anyways, here's the car as it sits at the moment...



Obviously it's quite a bit of a different driving experience than my 2014 GT but the times I've driven it, it's been a blast. Since I picked up the car, I've fixed (mostly) the horn, replaced inner seat belt sleeves, returned the cold air intake back to stock (and added a K&N air filter), added new hood bumper stop things, updated some other random hardware, and changed the oil. I've also got a fuel filter and some new sway bar end links that I'll be installing soon.


The battery (brand new) has died on me a couple of times. Now it is completely dead. Ordered a trickle charger and am now patiently waiting for it to arrive....probably won't be here until middle of next week. I've also ordered a heat gun so I can replace the center molding stripe. In the meanwhile, I pulled out the battery and I'm taking the drill/wire brush to the rust on the frame. Also have a POR-15 kit on the way.


Anyways, here's a link to my YouTube channel with a few videos of the small progress I've made so far. Cheers.

You Tube

 

Either the charging system is suspect or a short is present,draining the battery overnight.Id check the two fusible links on the alternator harness to make sure they're not blown.Id also verify the charge indicator lamp comes on as soon as you turn the key on.The lamp supplies the 12 volt exciter voltage that turns the voltage regulator on when the key is first turned on.Exciter voltage has to be present at the alternator,otherwise the alternator wont charge.
The picture at the bottom shows the wiring diagram which indicates where the two fusible links are located and the exciter wire route.
The battery also has to have a minimum of 12 volts
2 amps before the alternator will begin to charge.So less than 12 volts= an alternator that wont charge.

If you wind up having to replace the alternator,I highly suggest a 3G upgrade (even if you have no plans of modifying the car in the future) There are several vehicles you can grab one from at your local Pull-A-Part.Youll also need a 4ga power cable,4ga ground cable (run between the eec ground location and the neg battery cable ground location on the engine) & a mega fuse.You may need to grind a tiny bit of the alternator bracket to make the 3G fit,but its a quick job with a dremel or air powered cutoff tool.The sbftech link below lists the available vehicles equipped with this alternator plus other related info.

https://sbftech.com/index.php/topic,2679.0.html

 

Thanks wbrockstar. Lots of helpful details there...I'm sure I'll come back with some potentially dumb questions at some point as I progress on this. Speaking of which...

A viewer commented on a video of mine today that he noticed clips on the sun visor (from my first video on the fox) and said that I should check the vanity mirror lights. He said his were staying on and draining his battery and once he fixed that, he didn't have an issue any longer.

Obviously I can't check at the moment but I went back and was looking through some pics I took of the interior and one of the lights on the passenger side vanity mirror was on. I suppose that could be a possibility but can't really check just yet. I'd really like to replace the sun visors anyways.

 

In other news, I finally managed to get rid of the old yellow stickers on the inside of the quarter windows.....took a long time though.

Before


After


Got a new video up of some of this small progress:

You Tube

 

Yes indeed.If that light is remaining lit when the sunvisor is closed,it would definitely cause your drain issue.I assume the previous owner is the person responsible for the black electrical tape on the visor seen in the picture.It was likely his/her attempt at trying to keep the vanity light button pushed in when the visor is closed.The vanity light is powered through fuse #8,so to verify its remaining lit while the sunvisor is shut and its the cause of your battery drain,do the following:
Disconnect the neg battery cable from the battery post, attach the clip of a 12v test light directly to the battery cable terminal and touch the test light probe to the neg battery post.Is the test light lit up brightly?? If yes,rig the test light so that it will remain touching the battery post and go to the fusebox and pull fuse #8.Did the test light dim or shutoff completely?? If yes,that verifies the vanity light is causing the drain,so for a temporary measure,leave the fuse out for now.I don't believe that particular fuse has any important/necessity type components on it,so just leaving it out for now wont hurt anything.As a permanent fix,disconnect the harness plug from the vanity light to keep it from draining the battery.Im not 100% positive,but I believe the harness plug is either located under the passenger side A pillar trim (that runs down the windshield channel) or under the trim on the passenger side at the door/headliner area or it might possibly be under the headliner itself?? Once the plug is disconnected,you're good.

 

I didn't see your post until just now. Thanks again for chiming in. Copying and pasting an update that I've shared on a few other forums:

Interesting update on the Fox. I had a person comment on YouTube that I should check the lights on the vanity mirrors to see if they are draining the battery. Battery was out of the car, attached to trickle charger that just arrived so I couldn't see if the lights were functioning. I had taken a picture a while back though and noticed one of the vanity mirror lights was still on even though there was electrical tape across the little button. So I pulled the sun visors out (they need to be repaired or replace anyways) and disconnected the vanity mirror lights. That update can be partially seen in my newest video (just skip to the 9:00 minute mark):


So after this video...I hooked the battery back up to the trickle charger and let it charge over night. Yesterday, I threw the battery back in and the Fox started right up. I ran voltage test on the battery and it appeared normal. Even took the Fox for a little spin around the block.

This morning I checked the voltage again and it appears the battery is still holding a charge. I have some work to do but will try to start it again around lunch time and confirm that it's still holding enough juice to start the car.

Also, I ordered a PA Performance Premium Battery Cable kit that is supposed to be arriving today, so I'll be getting that installed as soon as possible.

 

Got the Fox to crank yesterday and the battery seems to be doing find holding a charge since being on the trickle charger over night and with the sun visors/vanity mirror lights removed.


Also, my PA Performance battery cable kit did arrive yesterday. Good stuff.

 

Thats good to hear.

 

The car has cranked with no problem a few times since I charged the battery and pulled the sun visors. Last night I replaced the old battery cables, which were in even worse condition than I thought, with the PA Performance kit. I couldn't figure out the alternator cable yet because I couldn't see where it was routed exactly...but I will try to get that installed sometime in the next few days.

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Do you have the oem amperage alternator (75 amp) or a 3G?? If its the oem amp unit,it uses 2 wiring harnesses instead of a cable.A 3G is the only one that uses a cable.