in my 85 gsl i am having a problem of a battery that wont hold its harge, despite being new. i get a jump and then drive for about 30 min at high speeds to charge it then when i get home i turn off the car and it wont start up again ever right afterwards. while i am driving i noticed that everytime i touch the brake all the lights in the car dim and the cd player restes it self any one with andy help is really apreciated

 

alternator

 

but does that explain the short with everytime i touch the brake?

 

its not a short its when u hit the breaks extra power is needed for the brake lights which u dont have so then u are underpowered for ur headlights and cd player cuz they are all sharing not enough power. so its not even a short basically just lack of power do to a bad alternator. easy fix

 

alternator in my bmw went and if i wasnt driving my car would actualy shut off. i lost pwoer and went dead while sitting in traffic then i decided it was time to change it over. lol . but it is easy as hell to fix and on an rx7 its not as expensive as my 250$ bmw alternator

 

Sounds more like a short in the harness than the Alt...

Start checking the wiring for cracks in the insulation, and corrosion...

 

If the alternator isn't pushing out at least +13v the battery will not recharge, and it would explain why the lights dim every time you hit the brake. But, if you're running a sterio system that puts a huge load on the battery and alternator this might also be a problem. It's unlikely, but it might be an issue.

 

enlighten me as to how this is not a classic alternator failure. not doubting you but ive lost 4-5 alternators on various cars and this sounds like it to me.

 

i agree. plus this alternator is probably old neways and its cheep enough id just replace it and chances are it will fix it. doesnt sound like a harness short to me but what do i know.

 

This is the perfect example of an alternator failure. It would be highly unlikely that it is caused by a short. A short would slowly drain the battery over time.

 

i know thats wat i was telling the other guy ^

 

I know, I was agreeing with you.^

 

ok then then were both in agreement then lol

 

I've driven with a bad alt before, and with a charged up battery, it wan't even noticeable for 15-20 mins...

 

I'd go ahead and put new battery cables on there, too.

 

When I had a bad alt all the idiot lights stayed on even after the car was started.

Most auto stores have an alt tester. Pull the alt and have them test it. If necessary, you can pull it in their parking lot.

You can get an alt at the junkyard for about $20. Or a rebuild at the autostore for less than $100. If you have the time (2-3 days) you can order from www.rockauto.com, which the cheapest, and they have good service. Check them out.

Make sure you get the right year: some years had internal and some had external voltage regulators.

B

 

That's if it really is the alt.

You might want to get a cheap voltmeter from radio Shack or Home Depot and then start checking voltages. One of the guys just found that corrosion on the battery clamp was enough to drop the bat joltage enough to cause problems, and that would also account for your problem. Invest in one of those cheapo battery wire brushes that reams the inside and outside.

You can also check the battery cell charge level with a cheapo hygrometer from the autostore. I'm still using the $3 unit I bought in, oh, about 1959.

These kind of electrical problems are common on any 20 yr old car, but they're cheap and easy to fix, too. Not as mysterious or complex or expensive as one might imagine.

B

 

Good point, he should check the battery cables and make sure they aren't gummed up. just keep in mind to check the cheaper things first, if it is a short somewhere that is taking enough of a load to drain the battery that fast then you could end up taking that whole car apart finding it.

 

i had the alt tested at autozoe and it came out fine but the worker said that i might want to try replacing the belt b/c it could be slipping b/c there was a lot of brake dust on the alt so i am about to start to cahng the belt

 

Do that and clean up your battery/starter connections and most likely you'll be fine. If not, then we can go from there...

 

can anyoen help to explain to me how to replace the belt b/c it appears complicated?

 

After a multimeter test, start with the cheapest, easiest necessary component, first: Battery cables.
You may be surprised how some bad battery cables can put the smack-down on our first gen electrical systems.

 

Clean your ****** battery terminals. Get a terminal brush and clean the **** out of them and the cables. That's your problem. Don't go droppin $$$ on a problem that's not there. Corrosion will cause that problem.

 

A while ago I had electrical problems. My battery was discharged twice on me while I was driving. The car just died and wouldn't start. I got a couple boosts from people but it wouldn't charge up enough to get going again.

I took the alternator to a local shop with a tester. (It's free.) It turned out the alternator was from a different year than the car so the connector didn't match what their book said. The alternator tested fine.

Get a voltmeter. You can probably find one for under $10 or $15. You want to measure the voltage across the battery and from the battery negative post to the "B" post on the top/back of the alternator. Both voltages should be really close. Maybe within 1/2 a volt. They should be about 13V when the car is running and idling.

In my case there was a difference of several volts when the car was running and a few volts when the car was off. This means there is too much resistance in the circuit between the battery and alternator.

Clean and/or replace the battery post connectors. Check wires for wear. If they look cracked, frayed, covered in white crystal stuff, etc replace them. I'm told a bit of baking soda and water can be used to clean that crystal stuff off but I've never tried. Disconnect the battery before you try to clean that stuff!

Check the three "fusible links" and the connectors for them. It is possible (and likely) that the metal at the connections have built up oxidization on them. You can try cleaning them and scraping them with a metal brush or sandpaper.

Also make sure all of the electrical connections are tight. Don't tighten stuff so much that you break it but if you have wire connections that are loose then they will bounce as you are driving and the circuit will be broken on and off.

Update:
Oh yeah daviddh85 pointed out a battery post cleaning tool. They cost something like $4 and you'll have it for years to come. That's the best part of buying tools: You get to keep them for next time. Or maybe putting them on the garage wall so people can see them.

 

i cleaned all the connections w/ sandpaper prior to posting this i am not a moron, but as i had said earlier that the belt was slipping all i need now is to knwo how to replace the belt since i cant seem to get the power steering pump belt off if anyone knows how i would much appriciate a post