Radio Shlock Cat# 22-218: $15.99. About the size of a box of cigs. I have a drawerful of digital multimeters ranging from cheap to laboratory-class, and use the RS unit more than all of them put together for dealing with automotive tests.

As you can see from the responses, you'll get a lot more help from here if you can check out some voltages.
--
Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD and 89 745 (LT-1 V8); hobbycar 77 MGB, and a few old motorcycles)

check the other end of the battery cable where it connects to the starter...
the alternator feeds the system through that location.
also check the ground straps/leads on the engine,
one at the back to the firewall,
one from the alt to the block (thats the one that got me)
and one from the batt to the fender and thence the block.

Do buy a meter...

Luck

I have to throw my hat in with the rest of these knowledgeable guys:

First wonder about it while you're driving.

Then, park it and run to the computer and consult the Brickboard.

Next, go back outside, open the hood and look for toast.

No toast? Clean up the battery terminals. Check the wires (3) at the alternator for being tight and looking good.

Find a friend with a meter and get him involved.

Change the regulator/brush assembly.

Keep us up to date on your progress;-)

-K

What is your system voltage with the engine running? If it is less than
13.5 volts either your charging system is not working well or something is
pulling it down (short or electrical overload).
Without knowing the system voltage, there's no way of telling where the problem
is unless you get lucky and see something (like the belt being off the alternator).
--
George Downs Bartlesville, Heart of the USA!

I would suspect worn brushes on the alternator. I had similar symptoms on my 90 and 91. You can buy the voltage regulator and brushes as one unit from FCP Groton and others.

Brian Mee
90 240 DL
91 240

If you or a friend has a voltmeter you can get a pretty good idea of what's going on. The procedure is to jump start the car, then check voltage and see if it's at least 13 to 14.5 volts or so. If not, the charging system is not doing its job.

Definitely by this time, you have a mostly discharged battery. My guess is that there's a problem in the charging system. However it's also possible that the charging system is doing what it should and the battery is just used up, internally damaged or corroded, and unable to be charged.

There's one low-cost (no-cost??) problem that could be happening. There's a thin wire going to a terminal on the rear of alternator, around two o'clock as you view its rear face. I had one 240 where that wire got worn and gradually got thinner and thinner. When it got real thin the red lights started glowing, and when it broke in two they came on full brightness. If I hadn't looked at it and repaired the wire it would have discharged the battery completely before too long. It carries 12 volts from the battery so be careful there. I think it's hot only when key is "on" but I can't promise that.

If you're advised that the alternator has gone bad, it's possible to replace only the voltage regulator portion. It removes from rear of alt. without removing the alt from the car. Costs a lot less, is faster and easier to replace, and usually does the trick.
--
Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors, quad horns. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Sounds like a loose/dirty battery cable, but at this point, the alternator is probably toast. Could be a bad battery, but check and clean the cables first.

Clean the battery cables, reattach them, recharge the battery and then start the car. Connect a volt meter across the battery once the car is running, if the voltage is around or above 13V, the alternator is "possibly okay". If the voltage is around 12V, the alternator or its wiring is toast.

Hope that helps.

jorrell
--
92 245 245K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently in pieces