Anyone rebuilding LH modules?

[JCM1]

Hi all,
Just used my last working LH module to cure my chattering fuel pump relay and would like to have the failed unit re-capped (assume the problems are due to old capacitors) as a backup/spare.

Is there anyone providing this service. My LH is from my 1992 500E.

Thanks in advance!


Joe

 

[gerryvz]

Not that I am aware of. Best to just buy a used one. Several folks have them for sale on the forum. Since your car is a 1992 model, you will want a "WOT" LH module. Those are generally a fair bit more expensive than the non-WOT 1993 and 1994 LH units.

You could certainly order the capacitors yourself and try to re-solder new ones in, but I'd still get a used unit.

 

[JCM1]

Thanks Gerry! Are there any wiring diagrams available? Also, found a couple of people who rebuild LH modules for Porsche 928s and have reached out but no response as of yet. I don't know what the differences are but both are Bosch.

All the best,

Joe

 

[gsxr]

Joe, there's a detailed thread on the forum with info about DIY'ing the cap replacement (edit - links below). If you can handle a soldering iron, it shouldn't be a big deal. Otherwise, any local electronic repair shop should be able to do it. It's getting hard to locate 1992 modules these days, and used ones may need new caps if the seller isn't guaranteeing it's click-free.

Links:

LH Module cross Test and Repair - Capacitor replacement | Electrical, CAN and Wiring

First, I have to say this forum is very good that I didn't seen before. Everyone share know-how and help each other. Some information I got from here and help me a lot. Today, share some information about my LH module repair and cross test with W140 M119 93' LH module. My car is 1992 EURO 500E...

www.500eboard.co

No fuel pump and buzzing relay | Electrical, CAN and Wiring

I need some advice please... When I turn the ignition on I have a buzz coming from the "central" rectangular relay (1/92) in the relay box behind the fuses; also the fuel pump does not run. The engine cranks but does not fire up. I have cleaned all the fuses but there does not seem to be a fuel...

www.500eboard.co

 

[JCM1]

Joe, there's a detailed thread on the forum with info about DIY'ing the cap replacement. If you can handle a soldering iron, it shouldn't be a big deal. Otherwise, any local electronic repair shop should be able to do it. It's getting hard to locate 1992 modules these days, and used ones may need new caps if the seller isn't guaranteeing it's click-free.

Thanks Dave!
I've just gone through a couple of weeks trying to find out how water has managed to find its way into the driver's and passenger's foot wells.
It turns out the front windshield had been replaced by the PO and they left a +/- 1mm gap on the trim piece along the top and had several missing clips along the side trim with rusted out rivets. Needless to say that's a big problem up here in rainy Vancouver. Fortunately, got the rivets replaced and siliconed the gap.

When I went to start the car back up - had the rear seat cushion off - I heard the fuel pump relay chattering so took my spare LH and replaced the faulty one and now all's well but I need to fix the old LH.

I opened up the LH and see a few capacitors that should be pretty straightforward to remove and replace.

I'll look for the DIY and will take a shot at it.

All the best,

Joe

 

[gsxr]

Hmmm. The windshield is sealed with butyl adhesive to keep water out. The trim pieces are just to keep debris out of the gaps around the glass, they don't keep water out of the interior. You may want to keep checking for the water entry point, especially the foam tubes below the heater box... if those disintegrate, you get water in the footwells on one or both sides.

More photos here.

 

[JCM1]

Thanks Dave! The attached picture and link you sent to others is most helpful. Those foam drains look really flimsy! Aside from condensed water from the AC what other water/moisture would accumulate in the heater box? Is it possible that the holes I had on the trim along the sides of the front windshield somehow provided a path to the heater box?

I think the rusted out clip mounts provided a way for water to enter behind the sheet metal which then accumulates and seeps out to the driver and passenger foot wells but I can't see exactly where. The sound deadening/insulating foam attached to the carpets on both sides were saturated with water. I'd guess there was at least a liter. The rusted out and missing trim clips were re-riveted and sealed so hopefully they are no longer providing a pathway for rain water to get inside the cabin.

All the best,

Joe

 

[gsxr]

Aside from condensed water from the AC what other water/moisture would accumulate in the heater box?

All water entering the air intake grille below the wiper, drains though the heater box, IIRC.

Is it possible that the holes I had on the trim along the sides of the front windshield somehow provided a path to the heater box?

I think the rusted out clip mounts provided a way for water to enter behind the sheet metal which then accumulates and seeps out to the driver and passenger foot wells but I can't see exactly where. The sound deadening/insulating foam attached to the carpets on both sides were saturated with water. I'd guess there was at least a liter. The rusted out and missing trim clips were re-riveted and sealed so hopefully they are no longer providing a pathway for rain water to get inside the cabin.

Ah, now I see, if the rivets were missing and there were holes open... that could have allowed water to get inside. But I'm not certain where the water would route to, if entering through the rivet holes.

 

[Sam SL]

I opened up the LH and see a few capacitors that should be pretty straightforward to remove and replace.

I'll look for the DIY and will take a shot at it.

Joe, I bought the capacitors at Lee's Electronics on Fraser and King Edward, in case you are moving forward with your DIY LH refurb.

 

[sheward]

Thanks for the picture. I've been wanting some as well.

drew

 

[JCM1]

Joe, I bought the capacitors at Lee's Electronics on Fraser and King Edward, in case you are moving forward with your DIY LH refurb.

View attachment 119388

Thanks Sam! In the LH module for my 1992 there is another capacitor in addition to the 22 and 100 uF . It is a linear one with leads on either end but the case is very poorly marked. You can see it in the lower left corner in the picture below. I think it is 47 uF 40v but can't be sure. BTW, I got my caps from Amazon - Nichicon KZ for the 22uF and KA for the 100uF from Amazon. Thanks for the info on Lee's Electronics.!

All the best,

Joe

 

[LukaszH]

Hello did you guys successfully rebuild lh module? Which capacitors need to buy and how many ? THX

 

[JCM1]

Hi LukaszH,
Yes, I replaced the leaking capacitors as per my post #11 above. Initially, I tried to remove the bad caps with just my soldering iron and that just did not work at all. I then researched a bit and found a desoldering unit and got one of these Pro's Kit SS-331 units for ~ $160 at Bangood.

Pro'sKit SS-331H Electric Solder Sucker Desoldering Device Anti-static High Power Strong Suction Desoldering Pump for PCB Circuit Board Repair

Only US$170.99, buy best pro'skit ss-331h electric solder sucker desoldering device anti-static high power strong suction desoldering pump for pcb circuit board repair sale online store at wholesale price.

www.banggood.com

I replaced all three 100 uF and all 3 27 uF however, I left the linear cap in place as it looked to be OK.

I recommend the de-soldering unit as its cost is small relative to the cost of a new LH module and it certainly made it a lot easier to remove the fault caps. The de-soldering unit has a vacuum system attached to the heated hollow tip which fits over the solder joint. Once the solder liquefies, you pull the trigger that the molten solder gets sucked out of the joint and the cap releases from the circuit board.

Get some flux too to assist. OVerall a small learning curve but pretty easy.

All the best,

Joe

 

[Duh_Vinci]

Those original frako capacitors will all fail eventually.

Cheers! Since eventually I will have to take care of those capacitors, there are so many! Is there a difference (if value the same)? For example, would these Panasonic units be good for replacement?

Panasonic such as these 100uf 50V and Panasonic such as these 22uf 50V ? Is there a better brand/quality to look for?

Regards,
D

 

[gsxr]

Based on other posts, I think both the capacitance rating AND the voltage rating are critical. Match what's currently in the module.

 

[Duh_Vinci]

Yep, matched the values. But since I have to order these online, we have no local stores here that sell electrical components, there so many brands out there, Nichicon, Juadong, Panasonic, Elna, Uxell, etc... Wondering if one brand is better than the other to use in the car environment?

 

[Jlaa]

Yep, matched the values. But since I have to order these online, we have no local stores here that sell electrical components, there so many brands out there, Nichicon, Juadong, Panasonic, Elna, Uxell, etc... Wondering if one brand is better than the other to use in the car environment?

OWNER - a777fan (E420) | Owners and Their Cars

Plugs, wires, caps, rotors, insulators, and coils all new. Next upstream electrical is to swap EZLs, Egas, and LH modules to see if there's a difference. Wondering if any of those could be responsible for intermittent misfires? Hmmm... IMHO those other possibilities are getting slim on the...

www.500eboard.co

OWNER - a777fan (E420) | Owners and Their Cars

Plugs, wires, caps, rotors, insulators, and coils all new. Next upstream electrical is to swap EZLs, Egas, and LH modules to see if there's a difference. Wondering if any of those could be responsible for intermittent misfires? Hmmm... IMHO those other possibilities are getting slim on the...

www.500eboard.co

 

[LukaszH]

Hi LukaszH,
Yes, I replaced the leaking capacitors as per my post #11 above. Initially, I tried to remove the bad caps with just my soldering iron and that just did not work at all. I then researched a bit and found a desoldering unit and got one of these Pro's Kit SS-331 units for ~ $160 at Bangood.

Pro'sKit SS-331H Electric Solder Sucker Desoldering Device Anti-static High Power Strong Suction Desoldering Pump for PCB Circuit Board Repair

Only US$170.99, buy best pro'skit ss-331h electric solder sucker desoldering device anti-static high power strong suction desoldering pump for pcb circuit board repair sale online store at wholesale price.

www.banggood.com

I replaced all three 100 uF and all 3 27 uF however, I left the linear cap in place as it looked to be OK.

I recommend the de-soldering unit as its cost is small relative to the cost of a new LH module and it certainly made it a lot easier to remove the fault caps. The de-soldering unit has a vacuum system attached to the heated hollow tip which fits over the solder joint. Once the solder liquefies, you pull the trigger that the molten solder gets sucked out of the joint and the cap releases from the circuit board.

Get some flux too to assist. OVerall a small learning curve but pretty easy.

All the best,

Joe

Thx

 

[LukaszH]

Ook thx going to do soon my really clicking like crazy

 

[Duh_Vinci]

OWNER - a777fan (E420) | Owners and Their Cars

Plugs, wires, caps, rotors, insulators, and coils all new. Next upstream electrical is to swap EZLs, Egas, and LH modules to see if there's a difference. Wondering if any of those could be responsible for intermittent misfires? Hmmm... IMHO those other possibilities are getting slim on the...

www.500eboard.co

OWNER - a777fan (E420) | Owners and Their Cars

Plugs, wires, caps, rotors, insulators, and coils all new. Next upstream electrical is to swap EZLs, Egas, and LH modules to see if there's a difference. Wondering if any of those could be responsible for intermittent misfires? Hmmm... IMHO those other possibilities are getting slim on the...

www.500eboard.co

Between you and @a777fan information on those posts and digikey.com - just learned so so much Selection is amazing, just need to research the capacitors needed for the cluster (surely that day will come and I want to be ready), want to order all in one setting. And looks like UBW and UBX line of Nichicon it would be...

Thank you all very much for the education!!!

Regards,
D