Bl**dy aircon failed..

[Ben Longden]

The blower in the W140 has been decidedly uncool of late.... compressor on, but NO fan. So any ideas?

By the way, THIS is what we are getting here.



Had to head to a town 250km from me to film a story on the heatwave for the news.... and twas a tad warm on the way!

 

[television]

Probably the carbon brushes worn out on the motor

 

[exjagman]

The blower in the W140 has been decidedly uncool of late.... compressor on, but NO fan. So any ideas?

By the way, THIS is what we are getting here.



Had to head to a town 250km from me to film a story on the heatwave for the news.... and twas a tad warm on the way!

It's 10 degrees C here and raining

 

[Ben Longden]

Took matters into my own hands as the auto elects are booked out for a fortnight...

Undid the four hundred zillion self tappers that hold the air vent facia together under the bonnet...

Then the four 1/4 inch self tappers and gently raised the facia away from the air vent....

Result; seeing one uber manky air filter... that was black as an abos bum and filled with all sorts of crud. Obviously there since new... 1992.... as the seals on the self tappers were untouched.

Gently lifted that out of place and revealed the blower motor with resistor in place.

The blower freely spins... which I guess is a good thing... so got the part numbers for the filter and resistor and promptly orderd from eBay.....

Now waiting..... meanwhile its 43 degrees outside....

When I was doing this, Jen checked the connection of the resistor. It moved together by about 5mm.... and I was hopeful this looseness may have been the issue. Alas... not to be.

(Jen is a super car freak, known to be ultra-passionate about her cars and not afraid of using common sense or getting hands dirty.. two of a zillion reasons why I love her)


The condition of the filter can be seen under the serial number....






Then the blower assembly;






And finally the resistor.



For fellow W140 owners, I hope you can read the part numbers ok..


A friend of mine has told me the resistor is more likley to fail before the blower.

 

[television]

It often is the reg pack on most,or the carbon brushes sticking or worn out.

It is not by the way a resistor in any shape or form, it is a solid state device

 

[television]

Ben, do get a tube of heat sink compound for when you mount the new reg pack

 

[Ben Longden]

Hi Malcolm,
Done that...

The latest on the W140 is that aftger a few tests, its the carbon brushes needing replacement.

Sad thing is my local auto elect is a sour old bastard, and does not really give a stuff about repairing it...

So, now on the lookout for another local or Melbourne auto elec who does give a rats, and is genuinely interested in assisting....

For what its worth, I powered up the fan, and it would not turn until the power contacts were pressed downwards towards the motor.. then it was operational.

Watch this space for the continuing story.....

 

[Ben Longden]

Changing the car, not the subject to my W124, it too has an AC issue.

On start, the AC runs fine, but after about a K, it stops.

An AC mechanic says the compressor is fine, gas is OK and there are no leaks. He has checked the wiring to the best of his ability against the Circuit diagram drawn by mr Haynes in his book, and feels the possible culprit might be the Climate module.

Any thoughts?


Photo;
The prime suspect.

 

[rf065]

that was black as an abos bum

It's 2014, not sure you can still say things like that. :lol:

Russ

 

[Ben Longden]

It's 2014, not sure you can still say things like that. :lol:

Russ

Lol... read my signature yet?

Back on track... any ideas re the control module?

 

[television]

You must have some shops that repair power tools, they all keep carbon brushes, they are dead easy to file down to size, if to do that always take off the sharp edge on the corners.

I will try and find some info on the 124.

 

[Ben Longden]

I never thought of that!
Thanks Malcolm!!!

 

[Ben Longden]

Update on the W124...
I paid a visit to Mercbits of melbourne today, and the guy there was brilliant.
He tried three different relays on the W124 Climate control (next to the ECU) and none worked... so my relay must be OK.
Oh well, thats one check box ticked.

 

[Ben Longden]

Update on the W140...

I sourced a new air filter, but the morons supplied me with a right hand drive version, so Ive been busy with a scalpel and glue fixing the new paper into the old frame. Love the smell of glue.

Seems to be a lot of slack MB mechanics around, as the car has had the same cabin air filter since 2001! So much for "book" services....

Anyway,

I found another auto elec. Well, its the same bloke but he is on his meds... and he had a really good look at the motor in the blower and found that it was simply worn out. Not only the carbon brushes but the bearings were worn (wobbly). So, she was going to need a new motor anyway...

So, I sourced another motor and it was a simple swap over... then clean out the blower bay and refit .

So I did, almost... I decided to plug it in first and see what would happen. Ignition key out, car safe... plug connectors together.. VRROOOOOMMMM the fan started up full throttle.

Not supposed to do that, I thought, so I swapped the resistor pack thingy over to the old one.

Silence when plugged together.... so into the cabin, and switch on electrics... IT WORKED!

Acid rest. Rotate the fan speed control.
Minimum; fan slowed down.
Auto, she sped up..
Max; she went faster...

So now to give her a road test....

 

[Ben Longden]

Update on the W124
(No cold air, compressor kicks in then out seconds after startup. Blower fan OK)

Courtesy of Mr Hayne, I got an AC mechanic to check the system.
Compressor is fine. Gas level is fine. Suggestion made to swap AC gas over to LPG as this cools faster.... (Any opinions?)

Wiring and connectors to compressor OK.

The Auto elec (on meds.. see above) did a quick test, and confirmed all fine with compressor electrics. Checked over pressure switches in engine bay and associated bits. All OK.

Engine bay located relay OK (Thanks to Mercbits of Melb who checked it using three of their own realys)

The man on meds had a good look at the wiring diagram, and came to the conclusion the next thing to check is the thermostat....

This is where I need help. Am I correct in thinking its in the overhead console next to the roof slide switch? (Item 110 on diagram)

 

[Ben Longden]

Update on the W140.

Did the drive, and found the blower works, but the flaps that allow the air into the cabin DONT work.

Vacuum?

Where abouts should I look - as the red and green vacuum lines under the bonnet look and feel OK.

 

[ShivaYash]

Update on the W124

(No cold air, compressor kicks in then out seconds after startup. Blower fan OK)



Courtesy of Mr Hayne, I got an AC mechanic to check the system.

Compressor is fine. Gas level is fine. Suggestion made to swap AC gas over to LPG as this cools faster.... (Any opinions?)



Wiring and connectors to compressor OK.



The Auto elec (on meds.. see above) did a quick test, and confirmed all fine with compressor electrics. Checked over pressure switches in engine bay and associated bits. All OK.



Engine bay located relay OK (Thanks to Mercbits of Melb who checked it using three of their own realys)



The man on meds had a good look at the wiring diagram, and came to the conclusion the next thing to check is the thermostat....



This is where I need help. Am I correct in thinking its in the overhead console next to the roof slide switch? (Item 110 on diagram)

Hi Ben
Any update on this? My car has similar issues but the mechanic is pointing the finger of blame at the compressor, meaning £££s. Wiring is ok, gas is ok, condenser and receiver dryer are both new.


Sent from my iPhone using Tapatalk

 

[Ben Longden]

Update. its 2019.. and the W140 is still in the shop..

Vacuum lines are all OK, and getting vacuum from the engine.

Now looking at the possibility of the control unit failing...

The fan blows. The AC works.. but no air enters the cabin as the flaps are closed.

Thoughts?

 

[mioba]

Just a thought. You mentioned earlier that you had to re glue your ac filter.
Did you put it back together correct as these are usually directional with regards to airflow.

 

[LostKiwi]

If it's the same as a 129 there's a vacuum distribution manifold in the module coffin (the place where all the major ECUs hide). The manifold is known to crack and leak vacuum.