W124 - Cooling fan

[mekon]

just connected a feed from the battery and heard distinct clicks when the connection was made and broken, the clutch engaging and disengaging perhaps? the engine was off at the time, and i need a slightly longer lead my wire is about 4mm to short to make a proper connection

 

[grober]

The electromagnetic clutch should have a constant 12v supply with the ignition/engine on. The thermal switch "downstream" just earths the clutch to make it operate. Cant remember whether the 12v is supplied via a relay and fuse or simply a fuse. Once you have eliminated the fan clutch by a temporary 12V supply it will be time TO HAVE A LOOK AT THE FUSE BOX AND RELAYS.

 

[television]

Well that clutch sounds like its OK so you will have to work back to find the faulty sensor(switch.

Sadly I have no wriring diagrams this early, but its all in the Haines book

 

[mekon]

i wish i had a haines....

fuse box shows all fuses ok

going to follow the wire as far as i can, failing that ill wire in my own switch bypassing the sensor thing, low tech all the way!

 

[mekon]

grober - the clutch wire is permanently earthed.... the sensor can only control the 12v supply im afraid

 

[grober]

Not according my old haynes 190 manual (basically the same engine) but maybe different on your car?

The fuses may be intact but on older cars there can be significant corrosion on the fuse contacts-the solution is to rotate the fuses in their clip contacts to make a better connection. If that restores the supply a more thorough contact clean is advisable.

EDIT CORRECTION in the W124 Haynes it is the other way round as you say. powered from fuse 7 in the fuse box which in turn is powered via the ignition switch.

 

[mekon]

great minds think alike grober i jsut rotated the fuses lol, otherwise i am considering wiring the fan into something like the rear window de-mister, can leave that on without any problems.... think i need to go pilfer a haynes manual from somewhere

 

[television]

Not according my old haynes 190 manual (basically the same engine) but maybe different on your car?

The fuses may be intact but on older cars there can be significant corrosion on the fuse contacts-the solution is to rotate the fuses in their clip contacts to make a better connection. If that restores the supply a more thorough contact clean is advisable.

EDIT CORRECTION in the W124 Haynes it is the other way round as you say. powered from fuse 7 in the fuse box

I did not know there were 2 different ways, as in the start I used the 190 way, so at least something learned

Do what grober say and clean all of the fuse holders with a non drying switch cleaner, that will prolong the life of the fues box

As you heard the click when you tried the live feed with the engine off the fan should not turn.

This is at the end of the day controlled by a temp switch so should not be too hard to find, a single pole sensor could drive a relay to provide the 12+ to the fan

 

[television]

89 could be the one

http://www.detali.ru/cat/oem_mb2.as...GM=717.430&CT=F&cat=506&SID=54&SGR=040&SGN=03

 

[television]

One more

http://www.detali.ru/cat/oem_mb2.as...GM=717.430&CT=F&cat=506&SID=54&SGR=255&SGN=07

This is the engine wiring harnes

 

[mekon]

i think fuse number 7 is about to get a closer inspection! cleaning and testing! the clutch is definitely functional, had the engine running and used the bypass trick.... almost got blown away! might ask at gsf to have a look at a thermal sensor, then look under the bonnet to see if it is what i think it is

 

[mekon]

fuse number 7 decided to break up on exit so.... it got replaced with a shiny new one that may or may not have originally been in my dads beemur *looks innocent and whistles*

 

[television]

With an Email address I can send you the picture of the sensor and lay out to solve your problems

 

[mekon]

either gmail is being uber slow or that email is another object lost to the web.....

try

oracle_of_computing at hotmail.com

 

[television]

cat gmail dot com

Go to edit and remove address

Page sent let me know if you get it

 

[television]

The EMail has been returned as un readable

I inserted the @ but it did not work.

Email me

 

[mekon]

email received, the twin pin sensor was the temp sensor as i suspected, given the dodgey fuse in 7 im going to try shorting the sensor again see if that engages the clutch, hopefully it will, then its just an 8.50 temp sensor to solve my woes... if not im going to find the nearest child and squeeze it into the engine bay to hold a wire directly disabling the clutch LOL

 

[television]

Sent again

 

[mekon]

huzaah!!!! shorting the temp sensor now activate the fan!!!! next time the car is used going to let it idle, watch the temp and if the fan doesnt kick in then i know its a duff thermal sensor and an 8.50 fix
w00t!!!

my hearty thanks to everyone of you who helped with this little problem

 

[Niks]

I had a similar problem with my fan, when I was stuck in traffic the temp used to heat up to 100+ (before the problem it used to average 80) and the engine started feeling really sluggish.

With the engine running, wait till it heats up a bit around 80, and try to gently stop the fan from spinning. If its really easy to stop and takes a while for it to spin up again, its the whiskus disc that probably needs replacing. It has some sort of a jelly in it which expands and locks the fan to a mechanism which spins it to cool the engine down.

Once the disc was replaced, the fan was alot more firmer and harder to stop when the engine is running. Plus you can tell its working as the noise of the fan running makes the engine sound more beefier!

Im not saying this is the exact problem, but its just a suggestion that it could be. So have a look there if all else fails.