Charge and Brake Warning Lights Stay On

[stanrob]

Starting a couple days ago, when I run my 85's engine, the Charge
and Brake warning lights BOTH stay on, no matter what. (Prior to
that, neither one stayed on.) The Charge fuse tests OK. Adding brake
fluid had no effect. Viewing the Svc Manual's wiring schematic, I'm
thinking alternator failure (for example a worn-down brush at
297,000 miles) might cause BOTH of those lights to stay on. Does
anybody agree or disagree? (A rebuilt one is $95 here - ouch!)

[Mark]

Every time I've had an alternator failure, both the charge and brake lights have come on. The brake light comes on a bit dimmer than the charge light. To make sure, check the battery voltage with a voltmeter when the car is shut down then check again with the car running. The voltage should be a volt or so higher with the car running. I wouldn't buy a replacement alternator without taking the old one apart and checking the brushes. They are held against the rotor with little springs, but eventually the brushes get so worn down that they don't make contact anymore and the alternator doesn't output any electricity. The brushes can be replaced for a few dollars and a soldering iron. The picture below shows one, but there are actually 2 brushes. Anyways, before taking it apart, I'd check to see if it's putting out voltage before taking it apart. It might just be a wiring to the warning light problem.

alternator.jpg

[dlb]

charge and brake lights staying on are a common sign of either battery or alternator failure. use a volt meter to test them. with the engine running, the battery should show about 14 V. if it's too low, the alternator is the culprit. with the engine off, the battery should show 12.5-13 V. if it's low, the battery is the culprit.

if both are low, it's probably just the alternator's fault since the battery is being used but is not being recharged by the alt.

[Mark]

Ha! We both must have clicked "submit" at almost the same time!

[dlb]

you beat me by a minute, you devil!

[stanrob]

Two answers in 48 minutes, wow!! Thank you for confirming my suspicion of the cause. (I was sleeping, saw them this morning.) I salute you, Mark and dlb. (Mark, your diagram from page CH-7 is for the type with no integral regulator, which I'm guessing you have in that beautiful 84; I have it in my 83 hatchback parts car, but for my 85, go to CH-14. Of course the brushes issue applies anyway.

Now I have new brushes in a box ($4.19+tax), the alternator out and its cover off, and I'm once again running into a brick wall. The brush holder's Philips head mounting screws are resisting my serious efforts at removal. I'm trying with Craftsman #2 and #1 screw drivers, having applied drops of oil, but no go. Is there a secret way around this? By the way, my surmise that I have 297,000 miles on that alternator was wrong: the reman label proves otherwise.

[Mark]

I'm pretty sure mine does have the internal regulator. I just grabbed the first picture I saw in the FSM that showed the brushes. I replaced my brushes over a year ago so my memory of it is fuzzy. The only screws I remember were the long ones that hold the whole alternator together. I do remember that those were ridiculously hard to unscrew. I used oil, let it sit overnight, but I ended up just stripping the heads. In frustration I abandoned it on a bench at work and some charitable co-worker got the screws out for me using vise-grips and a torch to heat them up.

[Mark]

Looking at the FSM, do you mean these screws?

rectifier.png

I remember that these ones came off easily for me.

[dlb]

regarding stuck screws, i rebuilt a carb recently and ran into a few that i was quickly stripping. i found an easy solution was to put a pair of needle nose vice grips on the heads of the screws really tight and give them a twist. this broke each of the screws free really easily and i was then able to undo them the rest of the way with no problems.

[Petros]

use AFT as penetrating oil (best stuff for breaking free rusted parts), apply heat concentrating it to the female end to make it grow larger than the male part. Also, sometimes giving it a sharp whack with a hammer will assist in breaking it free. It sends shock wave through the part.

good luck.

[stanrob]

I'm really impressed with your speed in responding, Mark and dlb, and I really appreciate your thoughtfulness. Will you forgive me now for throwing in the towel and paying $$$$ for another reman? The fates are not on my side! I'm 73 with a variety of health problems, a beautiful but impatient partner, and depleted energy.

I did try my narrow-nose visegrips; they just barely reach straight down to those @@@@ screws, and no matter how tight I make the jaws, they just wiggle in the tiny space. Hoping to get a purchase from the side, I tried to remove the regulator (its screws came out but the regulator wouldn't budge); then the rectifier holder (all four of those screws had exactly the same problem). Using a torch would damage the rubber brush holder cover. Looking forward, I had not yet tested whether I'm properly equipped for soldering.

P.S. Mark, regarding your drawing from FSM CH-8 (wrong section!): I'm OK with nuts. Screws are my problem. But thank you for your sympathetic effort. Seeing your 84's pic turns me green with envy! Does it still have full power, like my 297,000 mile 85?

[ARCHINSTL]

I'm 73 with a variety of health problems

OT, but - OMG! Someone besides me born in 1940?
I guess I have to share the ermine.
Tom M.

[marlinh]

Try an impact driver.

[stanrob]

OK, I've got the new reman. Mounted and wired. Works fine, the warning lights go out. For me, even that simple installation was hard, but at least I get the satisfaction of a fix.

[Mark]

Seeing your 84's pic turns me green with envy! Does it still have full power, like my 297,000 mile 85?

It has enough power for me. I've never done a compression test on it to see how far off I am from when it was newer. It has nowhere near the mileage (154,000) that yours has, but I hope to get it there.