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'93 300GE LWB
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Discussion Starter #1
Hi everybody, today I discovered that my diff locks deactivate itlsef after about 15 seconds and can't be activated afterward. And for some reason it can only be activated soon after the ignition key switched on (engine on/off), if I wait a little longer (3-5 minutes) after the ignition key switched on then the diff locks won't go at all. It was working just fine about 3 months back.

I've checked what I think is responsible (because it makes sound when I try to activate the diff locks):

I tried unplugging it's power and activate the diff lock but still the same result, it shuts off itself (because the light at the diff lock buttons is turned off) and can't be activated afterward...
Do you think that "the thing" is broken? Or is it possible that this is changing to be an electrical problem?

Please give me some advice, I really don't know what stops my diff locks from being activated :crybaby2:

Thanks.
 

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93' 300 GE
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My friend had a similiar problem on his 350 GDT. I think you've a problem at the timer that disengage diff-locks when the ignition key is switched off (after about 30 seconds).
Take a look at the fuses (n.10 in particular) and at the relay n.10 ;-)
 

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'93 300GE LWB
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Discussion Starter #3
My friend had a similiar problem on his 350 GDT. I think you've a problem at the timer that disengage diff-locks when the ignition key is switched off (after about 30 seconds).
Take a look at the fuses (n.10 in particular) and at the relay n.10 ;-)
Hi Ace, thanks for the advice :D
I've checked fuse number 10 in the fuse box under the glove box and it's in good condition, but I can't found the relay that you mean. Did you mean the K40 relay box, where is it resides in 300GE? (please pardon my ignorance :eek:)
 

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93' 300 GE
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Hi Bapao
The timer I'm talking about is in the "electric box" under glove box, near the fuses.
Its name, looking at MB repair manual is N11/7... you can see it in the pic, is the n.10 (sorry if it's in Italian).
You have to check if, when you disengage the diff-lock, it works (you can heard a "tick-tick" sound).
Hope that this will be of help...
 

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'93 300GE LWB
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8 Posts
Discussion Starter #5
Hi Bapao
The timer I'm talking about is in the "electric box" under glove box, near the fuses.
Its name, looking at MB repair manual is N11/7... you can see it in the pic, is the n.10 (sorry if it's in Italian).
You have to check if, when you disengage the diff-lock, it works (you can heard a "tick-tick" sound).
Hope that this will be of help...
Ace, you're 100% right on the spot!
I tried temporarily changing the timer relay with regular relay (for electric windows) and it works :D
But there's another problem now, the rear diff lock wont disengage, the red light still on even after several attempt to activate then disactivate it again. When I use the car for regular driving, I don't feel the rear lock engaged. So now it's yellow light off, red light on. When I activate the lock it's locking though (yellow light on, red light on)...Maybe it's mechanical now?

Anyway, big thanks for your direction and help :thumbsup:
 

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93' 300 GE
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Well, that's strange !
If you turn off the engine and after a while, switch the key on, the red light is still on ?
I'd try to use a new N11/7 relay, the "new" problem seems only an electrical contact, if you feel the car "normal" when driving.
I can't help you.. sorry
 

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'93 300GE LWB
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Discussion Starter #7
Well, that's strange !
If you turn off the engine and after a while, switch the key on, the red light is still on ?
I'd try to use a new N11/7 relay, the "new" problem seems only an electrical contact, if you feel the car "normal" when driving.
I can't help you.. sorry
You already helped, because you're right. Out of curiosity, last night I lift all four wheels, turn on the engine, activate the lockers, put in first gear and the lockers engaged, deactivate the lockers and they all disengaged, all seems to work properly except for the red light. So I guess that confirms it as another electrical failure and got to find the electrical scheme for the diff locks. I haven't get the chance to buy a new timer relay though (working class guy, have to wait for weekends :p).

Thanks :D
 

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brabus G36
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I think I have a similar problem with my 91 G and always thought that it was the relais. But did not want to buy one without a confirmation from someone else. I think I have this confirmation rightnow. Do you know how much they ask for the relais? If I remember well a european dealer quoted me something around 99 euros.

Have you done a test with the electric window relais? Relais number?
Are those relais repairable?

thanks
 

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'93 300GE LWB
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Discussion Starter #9
I think I have a similar problem with my 91 G and always thought that it was the relais. But did not want to buy one without a confirmation from someone else. I think I have this confirmation rightnow. Do you know how much they ask for the relais? If I remember well a european dealer quoted me something around 99 euros.

Have you done a test with the electric window relais? Relais number?
Are those relais repairable?

thanks
I don't know how much the timer relay cost, I've been searching for it for almost a week now and haven't find it yet here in Indonesia. The other regular relays cost me around 2 US dollars or about 1.5 euros. I don't think the relays is repairable...

I've tested the diff locks with regular relay (like the electric windows one) and it worked, but then the red light on my rear diff lock button won't go off until I unplugged the wire of the electrical switch on the rear slave cylinder. This may be caused by the replacement relay which doesn't work exactly like the timer relay :confused:

I've know another G which have even weirder problem in this area.
When the rear diff lock button is activated then the front one got engaged, when the front diff lock button is activated then the rear one got engaged, the center is working fine...
I think this is another relay problem. Or is it possible if the owner installs a new stereo head unit and mess the wires accidentally? What to check beside relays?

Thanks :D
 

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96 G300DT
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...

I've know another G which have even weirder problem in this area.
When the rear diff lock button is activated then the front one got engaged, when the front diff lock button is activated then the rear one got engaged, the center is working fine...
I think this is another relay problem. Or is it possible if the owner installs a new stereo head unit and mess the wires accidentally? What to check beside relays?

Thanks :D
The "wrong locker engaged" problem is simply a wiring or plumbing mistake caused by a clueless mechanic. To fix this they need to lift a rear wheel with the transfer case in neutral. Be sure to prevent roll-away. Then engage the center and rear locker. Spin the rear wheel. If it locks up then the correct locker is being engaged and the sensor wiring is at fault (front sensor wire switched with back sensor wire). If the rear locker isn't engaged then you know it is the front locker that is engaged. Follow the vacuum plumbing next to the brake booster and you will find which two hoses were swapped.
 

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'93 300GE LWB
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Discussion Starter #11
The "wrong locker engaged" problem is simply a wiring or plumbing mistake caused by a clueless mechanic. To fix this they need to lift a rear wheel with the transfer case in neutral. Be sure to prevent roll-away. Then engage the center and rear locker. Spin the rear wheel. If it locks up then the correct locker is being engaged and the sensor wiring is at fault (front sensor wire switched with back sensor wire). If the rear locker isn't engaged then you know it is the front locker that is engaged. Follow the vacuum plumbing next to the brake booster and you will find which two hoses were swapped.
Hi Alan.
He did lift all four wheels when discovering that the wrong locker engaged, so it's an accidentally swapped hoses.
I will tell what you advised me, thank you very much :thumbsup:
 
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