'84 190D, EGR Module..???
 

Folks,

I have been resurrecting my '84 190D 2.2, manual, 5 speed.....it's now tagged, inspected, & insured......am still trying to find out why the tach does not work......behind the battery is a socket.....empty when I got the car.....socket has 12 holes, in which there appears to be 9 connector sleeves......I don't know for sure what is supposed to be there.....but I think there is supposed to be an EGR Module.....the only reference to this (that I have found so far) is on Page 110 of the electrical schematics "Exhaust Gas Recirculation (Calif. Only with Manual Transmission) MY 1984 190D 2.2".....according to the schematic item N37 EGR Control Unit would have 6 used pins......but the Tachometer signal passes thru this item.....

Someone here should know what is supposed to be plugged in there?? and the part # if the proper EGR Module.....??

Someone here might know what I should jump to get the tachometer working....if possible....??

It also looks like this unit might also be necessary to resurrect the AC when I get to that point......

But the car runs sweetly, and I am getting about 40 MPG.....so I am happy without the tachometer....but it would be nice to fix it.....

Thanx,
SB

I have an '84 2.2 auto. If you post a picture of the plug, I can see what is plugged into mine if you think that will help.

Thanks, Matt

I believe that in your car's model year 1984, EGR is turned on and off depending on engine speed. The tach signal goes through the EGR module first, then to the tachometer. No EGR, no tach.

I just looked this up last week as I was troubleshooting an intermittent tachometer on my '84 190D-2.2 5-speed.

The tach signal comes from the A/C compressor control module. You don't need EGR to have a tach (but you do need the A/C compressor control module for the tach to work). My car came from the factory without EGR, so there is no EGR module. Unless your car is a california model, you won't have one either.

See page 118 of 290 in the Electrical Troubleshooting Manual (PDF copy). This page is marked 127. It shows the tach signal coming from a triangle marked 'B'.

Then, see page 264 of 290 (marked 309). It shows the "Engine RPM Output" coming from the A/C compressor control unit and going to a triangle marked 'B' (which refers back to the first drawing I mentioned).

The EGR module shown in the electrical drawings can be misleading since it may not actually be present in your car.

I can send you these PDFs if you don't have the manual I'm referring to.

The A/C compressor control module is located behind the battery (there should be a plastic barrier between the battery and the module). It plugs into a socket similar to what you have described and has ~9 wires going into it.

control unit/relay
 

See if you have one of these.
It's described as the A/C compressor and kick down cut-off.

(The give away is the second line on the "Rear" view Picture,
"D-Clima Kickdown".)

Assuming Cornblatt is correct, lack of this control unit /relay might explain
BOTH Tachometer and No A/C!

AND as we all know,due to Mercedes using "One Part for All" the pins used
by your car may not be all the pins on the relay.

Fastlane.

Hoowee! The price may be why it's left out.

Thanks...
 

Folks,

I have an '85 190E Automatic.....and both relays that were plugged into that car.......there was nothing plugged into this car.......

One relay....the rear one on the "E" has an obliterated label....
part # 001 545 8505 (not too sure about the last digit)....
obliterated line of print
5Wky 25B (not very sure of this) 12V
8 pins

The other relay from the "E"
001 5*5 78 05 * denoted unreadable character, most likely a 4
4Zyl.KVS Kickdown
05 8956 10 12V
9 pins

is the second module the same as the one used on the Diesel cars??

Thanx,
SB

I think that this is a Federal car......

I've attached a picture of what is in my car...

Thanx....
 

That's just what I needed.......

The module that I removed from the "E" is very close in number, which most likely means that it is way different......

Yours (photo)
001 545 81 05
D-Klima
05 8958 00 05 8956 10

The one that I have
001 545 78 05
4Zyl.KVS Kickdown
05 8956 10

I'll plug it in tomorrow and see if it does anything......the infamous "smoke test"......

SB

Based on the electrical manual, the two items appear similar, but not the same. Note that pin 4 is an output on the 190E relay and an input on the 190D version. This may cause problems if you plug in the wrong relay.

The RPM output isn't shown on the 190E relay either... :(

Here's the comparison:
Edit: What I'm comparing here is the A/C compressor control module for each model of car, under the assumption that these parts fit in the same socket. I haven't actually seen the 190E version or verified the part #... Also, in some places they call it a "refrigerant compressor relay", other places it's a "refrgerant compressor and kick-down cut-off control module", etc. which makes it a bit confusing.

Huh?
 

001 545 78 05 is a Fuel Pump Relay,with Kick-Down.
(remember what I said about Mercedes parts interchangeability)

That is the Fuel Pump Relay from a(Your?) 1985 190E

A/C Relay
 

What YOU want to plug into that "SPACE" (on the '84 190D) is: 003 545 69 05

Which must be the "Supersede To" number for Cornblatt's 001 545 81 05

******** gives you the correct part number when you plug in the Vehicle.

(And a much nicer financial monkey)

However as a "PathFinder" you will try the 190E fuel/kick-down,We may learn
that "RELAYS is Just Relays...An interesting experiment...I don't think any
SMOKE will be involved. It'll either cause the Tach and A/C to work or it won't.

EDIT: From Cornblatt's comparison diagram The Tach won't work
(PIN # 3 on the 190E relay should be "RPM output" (For the 190D),BUT
PIN#3 is blank so there will be no RPM.The A/C MAY work because the relay
MAY be able to compare the RPM input #2 with the compressor RPM #11.
ONLY if the Fuel/Kick-Down relay can make comparisons like the Klima relay
and activate the A/C clutch when the engine RPM and compressor RPM are
the same(or nearly).

Good Info.....
 

Guys,

Thanks, many thanks.....

Where in the electrical schematics did you find reference to those relays??
A page that lists the relays / modules??
Or did you just look at different schematics and note where the pins went??

Thanks for the data on the relay / module......

I'll try the unit from the E.......but am mot ready to work on the AC system.....but will try it just for info purposes.....

Looks like I can just jump pin 2 to pin 3 to restore the Tach.......I have some nice plug type Stakons (crimp on wire connectors) that might fit into the pin sockets for the relay / module......

Thanks again,
SB

Shooooottttt....!!!
 

Guys,

My module does not fit, due to the position of the locating pin......so now all I need to do is locate which pin socket is #2 and which socket is #3.......will report back later......

SB

Bump for Cornblatt
 

location of the "Pin Out" charts that you got the info for the comparison,Please!

Trail and Error method
 

Guys,

I got my Tachometer working by jumping ........


Car's Firewall
--------------------------
O X O O O O
X O O O O O
------------------
Radiator Tank

.......the sockets indicated by X

Thanx for all of the input......great info, Cornblatt.....you had to look that up yourself.......Thanx again!!

SB

I intend to work on the AC sometime in the future, will worry abut the rest of this circuit at that time.......