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New to the forum, glad to be here.

I have a 1989 420SEL w/ 196k on it. Dark Blue, Tan leather Interior, 18" Brabus Monoblock Vi's.

I love the car FYI.

So my question, My guage lights all went out randomly at the same time and i cant figure out what is wrong. I've checked my fuses and they all look good. I pulled the cluster out and nothing seems to be wrong. any help here?

Also, my radio(stock that came with car) started cutting out like every 30 seconds when i was using a tape deck adapter, then after it did that a few times it completely stopped working and displays "-------"
again, ive checked the fuses and cant seem to find anything wrong.

From my experience, the majority of cars have a seperate fuse box that is usually located under glove ox or something but i cant find one.

Can anyone help me out here?
 

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New to the forum, glad to be here.

I have a 1989 420SEL w/ 196k on it. Dark Blue, Tan leather Interior, 18" Brabus Monoblock Vi's.

I love the car FYI.

So my question, My guage lights all went out randomly at the same time and i cant figure out what is wrong. I've checked my fuses and they all look good. I pulled the cluster out and nothing seems to be wrong. any help here?

Also, my radio(stock that came with car) started cutting out like every 30 seconds when i was using a tape deck adapter, then after it did that a few times it completely stopped working and displays "-------"
again, ive checked the fuses and cant seem to find anything wrong.

From my experience, the majority of cars have a seperate fuse box that is usually located under glove ox or something but i cant find one.

Can anyone help me out here?
For the gauge lights, it might be the rheostat/dimmer switch, on the left hand side, on the back of the cluster. They can sometimes go bad, and sometimes can be repaired/cleaned. Almost easier to replace it-- and there are plenty available in JY's around here (So. Cal.)

As to the radio-- Not sure, but it just might be time to replace the ol beast. IDK how you feel about "stock" vs something a little more advanced (think iPod/mp3 player connectivity, etc). The problem can be that you have to do something a little more than minor surgery to replace a radio effectively (the stock system has the fader switch in the console and amps behind the rear seat). Replacing the head unit is doable if you have some experience with wiring, etc. Plenty of threads to read through on the forum....

There isn't a separate fuse box other than the one in the engine bay. A good idea to replace all of the original fuses with new COPPER ones, and take a Dremel tool with a soft wire brush or some emery cloth to all of the contacts. This can take care of a multitude of issues, and it might be the cure for the radio.

Oh, and welcome to the forum-- we like pics!!
 

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Discussion Starter #3
For the gauge lights, it might be the rheostat/dimmer switch, on the left hand side, on the back of the cluster. They can sometimes go bad, and sometimes can be repaired/cleaned. Almost easier to replace it-- and there are plenty available in JY's around here (So. Cal.)

As to the radio-- Not sure, but it just might be time to replace the ol beast. IDK how you feel about "stock" vs something a little more advanced (think iPod/mp3 player connectivity, etc). The problem can be that you have to do something a little more than minor surgery to replace a radio effectively (the stock system has the fader switch in the console and amps behind the rear seat). Replacing the head unit is doable if you have some experience with wiring, etc. Plenty of threads to read through on the forum....

There isn't a separate fuse box other than the one in the engine bay. A good idea to replace all of the original fuses with new COPPER ones, and take a Dremel tool with a soft wire brush or some emery cloth to all of the contacts. This can take care of a multitude of issues, and it might be the cure for the radio.

Oh, and welcome to the forum-- we like pics!!
thanks! what does this rheostat/dimmerswitch look like? there are a ton of JY's here to (seattle) that I'll be able to spend some time at next week. (gotta find parts for my bmw e30 24v swap too!)

ive always wanted to get a new radio/deck i've just never been able to save some cash up for it. all the $$ go towards the e30 at the moment, but i guess it might be time to get something new. my friend works for Best Buy audio installation so i'll talk with him.

Ive just recently read about replacing all of the fuses with copper ones so that is at the top of my list.

the car has actually never had working heat either so maybe doing that will solve that issue. From my auto knowledge it seems like my heater blower motor (or whatever the name is) isnt working. basically pushing any of the heating/ac buttons do nothing. no defrost or anything.

I'll get picks as soon as i can. I love showing this cruiser off. :) thanks for the suggestions
 

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The rheostat is on the back of the gauge cluster. Sorry I don't have a pic. It's white, and very oddly shaped. There are two metal strips on top: a short straight one, and a longer one underneath that has a 120 degree angle. By the way, this is adjusted by turning the little black knob at the bottom left of the cluster that you would normally push to reset the odometer. They develop dead spots, but sometimes you can get it to land on a live spot.

ElRojo covered the copper fuse issue, (and for future readers: the stock "tin" fuses are notorious for corroding at the ends. They stop working, yet don't look blown), so the only other thing I would add (and please tell your audio installer buddy) is this warning: You know that wall at the back of your trunk, the one right behind your back seat? The one that looks like an ideal place to mount an amplifier? That's your fuel tank. Many horror stories of people screwing into them.

Best of luck to you.
 

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Well, here's a pic to start. The dimmer rheostat is on the right in the pic. This particular pic is from a gen I car (it has a date of 2/83). You want to pull one from a post 1986 car (a gen II). It will look very similar, but there are differences. If the cars in your junkyards aren't too destroyed and clawed over (like some down here), you should be able to find a good cluster. If not, let me know and I'll see what I can dig up.

As to no heat-- you may need to replace the monovalve. And the climate control might have gone south, and there is also a special 30A fuse for the blower motor in its own little black box just forward of the brake fluid reservoir. Check the pic in this link: http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1264673-420-sel-blower-fuse-location.html#post1911034 The little box is about an inch and a half by half an inch, right in the center of the pic, with a big flat fuse in it. Replace this even if the one in there looks good.
 

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Discussion Starter #6 (Edited)
Well, here's a pic to start. The dimmer rheostat is on the right in the pic. This particular pic is from a gen I car (it has a date of 2/83). You want to pull one from a post 1986 car (a gen II). It will look very similar, but there are differences. If the cars in your junkyards aren't too destroyed and clawed over (like some down here), you should be able to find a good cluster. If not, let me know and I'll see what I can dig up.

As to no heat-- you may need to replace the monovalve. And the climate control might have gone south, and there is also a special 30A fuse for the blower motor in its own little black box just forward of the brake fluid reservoir. Check the pic in this link: http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1264673-420-sel-blower-fuse-location.html#post1911034 The little box is about an inch and a half by half an inch, right in the center of the pic, with a big flat fuse in it. Replace this even if the one in there looks good.
I'll replace that fuse for sure, the pic explains it all. What is this monovalve you're talking about though?

The rheostat is on the back of the gauge cluster. Sorry I don't have a pic. It's white, and very oddly shaped. There are two metal strips on top: a short straight one, and a longer one underneath that has a 120 degree angle. By the way, this is adjusted by turning the little black knob at the bottom left of the cluster that you would normally push to reset the odometer. They develop dead spots, but sometimes you can get it to land on a live spot.

ElRojo covered the copper fuse issue, (and for future readers: the stock "tin" fuses are notorious for corroding at the ends. They stop working, yet don't look blown), so the only other thing I would add (and please tell your audio installer buddy) is this warning: You know that wall at the back of your trunk, the one right behind your back seat? The one that looks like an ideal place to mount an amplifier? That's your fuel tank. Many horror stories of people screwing into them.

Best of luck to you.
WOW! i had no idea that that was a dimmer switch. Just went out to my car and turned it and gave my dash a little whack and bam! all my lights came on. THANKS! ive been drving with no gauge lights since july.

I'll get to replacing the fuses as soon as i get home (still at school right now and in finals)

and thanks for the heads up about the gas tank being there, i didnt know that either. Luckily I fiberglassed a 2 12" sub box into the trunk with matching brown carpet in that spot with plans to add a new stereo system but it never happened, so that wont be an issue. I plan on building another fiberglass mount for the amps. I'll take pictures of the box too, when i get a chance.


Thanks for all the help. I've spent massive amounts of time on r3vlimited.com researching my e30 project... i dont know why I've never thought of joining a benz forum. Just in the last few hours its given me awesome things to check with my car.

Looking forward to posting some pics...

here's the build threads of my e30 project if any of you would like to take a look. for some reason it's not showing up in my sig....

build thread: http://www.r3vlimited.com/board/showthread.php?t=192128

continued update: http://www.r3vlimited.com/board/showthread.php?t=215540
 

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You're very welcome. I'm glad I was finally able to help someone, since others have helped me so much! There are many knowledgeable, helpful people on here, and many topics are well documented, as I'm sure you've found by searching the threads.

Your BMW project looks great!! Looking forward to seeing your Benz, especially your stereo install.

Good luck with your finals.
 

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+1 on the Beemer-- looks great!

Love the look of the benz too. Nice looking wheels and what looks like a nice conditioned car. Now-- get some euro headlights on her and she will really be handsome!

As to the monovalve, it's what controls getting the heater operating. Basically a valve that allows (hot) coolant into the heater core so you get heat in the cabin. A common problem to have to repair on these cars. That being said, I would make sure of the electricals before going after this item. Still might need to get done anyway (and it probably wouldn't hurt as a maintenance item, but I'd go for bang-for-your buck stuff first).

The monovalve itself is next to the battery on the false firewall, underneath the electronic diagnostic box. This link will tell it all... type in mbz and then .org to replace the ********.

http://www.********/articles/hvac/plumbing/monovalve/

A BW discussion:

http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1590372-instant-monovalve-repair-kit.html#post4747199

parts: Bosch is $56, MTC (aftermarket) $27.

Your Parts Search Returned 6 Part(s)
 

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+1 on the Beemer-- looks great!

Love the look of the benz too. Nice looking wheels and what looks like a nice conditioned car. Now-- get some euro headlights on her and she will really be handsome!

As to the monovalve, it's what controls getting the heater operating. Basically a valve that allows (hot) coolant into the heater core so you get heat in the cabin. A common problem to have to repair on these cars. That being said, I would make sure of the electricals before going after this item. Still might need to get done anyway (and it probably wouldn't hurt as a maintenance item, but I'd go for bang-for-your buck stuff first).

The monovalve itself is next to the battery on the false firewall, underneath the electronic diagnostic box. This link will tell it all... type in mbz and then .org to replace the ********.

http://www.********/articles/hvac/plumbing/monovalve/

A BW discussion:

http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1590372-instant-monovalve-repair-kit.html#post4747199

parts: Bosch is $56, MTC (aftermarket) $27.

Your Parts Search Returned 6 Part(s)
i'll look into the monovalve more when i get home.

i didnt even know you could get Euro headlights for these. i had planned on getting OEM replacements from rock auto. they were broken when i got the car. theyve only gotten worse.

Anyone have problems with their Electro Hydraulic Actuator causing hesitation during acceleration and power loss?
 
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