My Temp gauge, Seatbelt light\Buzzer have gone crazy. In addition
apparently battery drains after setting say 8 hours. All indications is that this is a loose ground. Sure could use a diagram of where the Ground points are on a 1980 300TD Help Please. Note there are chunks of what seem to be Sound Insulation on the floor on both sides.

J-Bear,

I would first try to trace the cause of the leaking current that causes the battery to go dead. U might put a DC ammeter in series with either of the battery cables and the battery then remove one fuse at a time to see if opening any circuit stops the current flow.

P E H

Check your battery cables first, could be one or both is loose, corroded, insulation worn through, etc....

blkntancj,

Bad battery cables would not cause the battery to discharge when car is not used for 8 hours.

P E H

It could be a combination of both bad grounding and a failing alternator. In that case your battery is not getting fully charged. You need to look around the engine compartment ( fire wall and wheel wells) for any grounding studs and wires. On your age vehicle I would bet they are all oxidized. Wire brush them and open and retighten the nuts a few times..... and it would not hurt to coat them with dielectric grease (AutoZone) . Also check or have your alternator voltage output checked. It should be anywhere from 12.5 to 14 volts at idle. If the brushes are worn you might get that at speed but when you idle around in traffic the output could drop to almost ZERO.

Good Luck

__________________
FRED

Daily Driver: 98 E300TD 199K
Hobby Car: 69 Austin Mini
Past Diesels: 84 300SD, 312K
87 300SDL, 251K
94 Chev. K-1500 6.5Ltr.TD, 373K

Actually, I replaced the Alternator first. Looked at the old Voltage Regulator and it was worn but still decent. Returned,replaced the battery that kept losing charge ( 4 months old ). Haven't tried leaving the new one connected over long periods of time yet but it does ( when attached ) start much more strongly. Appreciate your responses. Anxiously awaiting more. Does anyone have a diagram. Those Vacuum Diagrams posted recently were excellent! Thanks

Do not let the fairly new battery drain down too far too often. They really do not appreciate it.

J-Bear,

Have U put an ammegter in series with the battery to see if there is a current drain?

How does a voltage regulator look worn? Or do U mean the brushes look worn?

P E H

The Brushes.

I had the test done with the old battery in and it registered at 12.5-13 as well as the Alternator. I was looking for higher but I guess 12.5 is acceptable. I replaced the Alternator anyway in that I got a great deal on it.

Thanks F18.
I though about what you submitted again. Today I couldn't start again and it was 63 Degrees. I took the battery (2 wks old) to be charged and it wouldn't take a charge. Replaced with another new one. I was foolish enough to think that I'd get a Battery Warning light if it wasn't being charged properly but I realize that's not necessarily the case.
I'm now going to clean the + Cable contact at the starter where the cable to the Alternator attaches (I think) as well. Apparently the battery is not getting charged. The cables don't seem to look bad but 'looks can be decieving'. That area seems oiled\gunked up anyway. If that doesn't do it I'll replace both cables. Hey, 'My Baby' is 27 yrs old I know it couldn't hurt.

Forget about cleaning up temporarily and check for battery drain with car off as others have suggested. You might not get another battery under warranty as easily in a few weeks.
Depletion of the battery seems to do irrepairable damage if repeated. I hope your past battery was defective when first purchased. Otherwise you might be in for the same ride.
It really makes me upset to find one of my newer batteries discharged. I suspect part of it's overall capacity has been taken. I automatically know the lifespan is reduced big time from experience. We are not buying deep discharge cycle batteries for our cars.
As a consequence they really do not want this type of treatment. Fairly easy to verify if you have abnormal drain or not. Multipal threads in archives as well.