1984 300Td completely dead - PeachParts Mercedes-Benz Forum

1971 280SE · #1 05-17-2017, 08:47 PM

Hello all, was wondering if anyone can give me some insight about my car..Car has no power at all to anything..all the fuses good and the battery is good..is there a main fuse that maybe I can run a new power wire to to power up car? It happened after a heavy rain storm, I noticed the little box on passenger side kick panel is soaked with water..it says EGR on it..it is some form of ECU it appears..Would that box stop car from starting? If someone can tell me where the wires from that little 3 pole junction box on passenger side go to I can maybe figure this out..I have shop manual but cant seem to find the correct schematic in there for it

ROLLGUY · #2 05-17-2017, 09:18 PM

You should have +12v on the two large terminals on the junction block. The smaller terminal is the start signal from the ign. sw. to the starter. You may have a bad ground. Check the - terminal cable on the battery and chassis. Also check the ground strap going from the chassis to the trans bolt on the left side. I suspect a bad ground, so look there first.....Rich

1971 280SE · #3 05-17-2017, 09:22 PM

Thank you for your help..I don't have the 12 volts on the 2 large terminals..would it be ok if I ran jumper wires from battery temporarily to test to see if that works?

ROLLGUY · #4 05-17-2017, 09:30 PM

Quote:

Originally Posted by 1971 280SE

Thank you for your help..I don't have the 12 volts on the 2 large terminals..would it be ok if I ran jumper wires from battery temporarily to test to see if that works?

If you put the - of your meter on the battery terminal, and put the + on different places on the + side, you should see voltage somewhere. If you have voltage on the battery terminals, and then move the - lead to the chassis and have no power, you have found the problem. Again, it looks like a ground problem. You need a good - to complete the circuit. Jumping the + anywhere will do nothing if there is no ground.

1971 280SE · #5 05-17-2017, 09:32 PM

Thank you for your advice..I will check in the morning..I made a temp ground with booster cables but I put on engine and not on chassis..I will try to sort this out tomorrow..I'll post back with what I find..

unkl300d · #6 05-17-2017, 10:08 PM

Does this 1984 model have a strip fuse for the glow plug relay? Maybe that is burnt out.
Your model might have that strip fuse inside the glow plug relay. Lift off the plastic lid from the glow plug relay.

ROLLGUY · #7 05-17-2017, 10:29 PM

Quote:

Originally Posted by unkl300d

Does this 1984 model have a strip fuse for the glow plug relay? Maybe that is burnt out.
Your model might have that strip fuse inside the glow plug relay. Lift off the plastic lid from the glow plug relay.

If there is no power on the junction block, the glow plug fuse is irrelevant.

1971 280SE · #8 05-18-2017, 10:48 AM

Ok I checked the junction block. The one in the middle has no power or grounder and the one closer to firewall has turned into a ground for some reason

tyl604 · #9 05-18-2017, 01:42 PM

Do you have a junction box on the right front wheel well with wires going to the starter and battery like on my 300SD. If so you can use two screwdrivers to short one of the wires to another and jump the starter. Just put one screwdriver on one screw and another screwdriver on one of the other screws (experiment to find the right combo) and touch the metal shafts of the screwdrivers together. If your key is on, it even might start. If off, it should at least make your starter work.

BillGrissom · #10 05-18-2017, 02:15 PM

My 1984 300D has 3 screws on the junction block, as I recall. The two big ones are connected together and are BATT+. The ALT output (2 wires) attaches there), as does a wire to the fuse box. The smaller terminal is the "starter solenoid". 1 wire goes to the solenoid (SOL) on the side of the starter, another wire comes from the key switch. If you jumper from the BATT+ to SOL, the solenoid should actuate (big electromagnet) giving a clunk and applying power to the starter motor (via separate thick wire straight from battery).

I wouldn't fool w/ the starter circuit yet. Since you have no lights in the cabin, see if the fuses that are "always hot" are getting 12 V (at inner terminals). I also 2nd RollGuy's "verify grounding". I found the thick ground strap from transmission to frame (driver's side) had corrosion. Noted that when I had the cluster pulled out and saw smoke from the speedo cable as I cranked the engine (was using that for return current).

tyl604 · #11 05-18-2017, 02:19 PM

Agree.

tyl604 · #12 05-25-2017, 01:06 PM

So what has happened in the last few days? Follow up please.

Adriel · #13 05-29-2017, 02:02 AM

Not to off track, but interesting seeing a rare '84 wagon without a turbocharger.

t walgamuth · #14 05-29-2017, 07:07 AM

Must be a euro.

barry12345 · #15 05-29-2017, 10:57 AM

Simply means that a battery terminal may have lost connection. Take the cables off and clean the connections. Probably this is the most common cause of your description. So the first thing to check. Then move on to other connections if the problem is not this.

To verify it is the problem. Just put your headlight switch on. Take your meters probes. Put one probe on the centre of each of the lead battery posts and the other on the surrounding cable clamp. If you read voltage you have found the problem.