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Driver Seat Ecu repair DIY replacing 3.6V battery

35K views 57 replies 24 participants last post by  Tom109 
#1 · (Edited)
Hello world,

I'm new to this forum, ;-)


driving a 1995 Classic RR, I had the seat ecu memory not working anymore, over a year ago I took the whole unit out, and had it in my livingroom until enough dust covered it.

Well, a few days ago, I thought I'm gonna finaly order a new 3.6V battery, the blue little Varta one.
I soldered the old battery out, and then thought, why not just replace the old battery with usual NiMh batterys?
I found three 1.2 Duracells and soldered them together. See Pics:







Putting every thing back under the seat, I ran the calibration (Handbrake, Ignition on, press five times the green button, following 2112), see Video.

Cheers, Chris
 
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#3 ·
well, it worked for about 60km, then I smelled soldering and when I was back home I opened the box, and the red wire was disconected. I don't know if it's because of the 800mAh instead of the 100mAh from the original-battery, or if it's because of the corroded IC's... no idea.
It's Land Rover, you fix a thing and then it works once or twice. Had the same with the Cruisecontrol, fixed it, it worked one day,since then, kaputt :?
 
#4 ·
The issue is that you put a NiMh instead of a NiCd. Don't mess with stuff you know nothing about ;-) They aren't compatible from a charging perspective.
Get a replacement button cell on ebay and solder it into place.
 
#11 ·
Good information. I just pulled mine out and as expected found the corrosion beneath the battery. It looks like the circuit board is not too bad, I had only lost a couple of functions. Not really wanting to pay $400 for the Proper Parts replacement how did you repair the circuit board itself? (I need to find a place to do that for me.) Does your seat work without the batteries installed, or are they necessary for any operation?

I over-rode the controls to get the seat to where both my teenage daughter and I could 'share' the position, so I have time on my side to try to fix this.
John
 

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#12 ·
Hello Hormel, From your photo that board doesn't look too bad. I repaired mine almost ten years ago, the seat smushed me tight up against the windshield one morning while I was driving to work `8) The replacement battery was easy to find then using the numbers on the old battery and a google search. I had more corrosion. I cleaned the board very carefully removing all the corrosion and some of the copper track to the battery. Had to replace one of the small orange ceramic capacitors too. Used a silver metal paint pen with a fine tip which is sold to repair damaged tracks on circuit boards, purchased a second pen that is a clear sealer to cover the freshly painted track and the areas where the original track was fine but I had removed original sealer and surface corrosion (might have found these at Radio Shack, not sure now) and soldered in a new battery. I then sprayed it with a light coat of CRC SP400 Extreme Corrosion Inhibitor. I use SP400 all over my Rover; think it is much like Waxoyl. Electrical issues are getting fewer each year. My Memory seat has worked perfectly since then, the spouses #2 button settings are very different from my #1 settings. Hmmmm, I'm probably due to replace the battery again. Wonder if a soldered in socket and a compatible but replaceable battery would be better.

The repair is easy if you take your time, have good light and maybe a magnifier. **** eyes get tired as you get older :?.
 
#13 ·
hi folks
i had the same problems with the seat ecu ..i change the battery...it was bad but there was not damage to the board ..i did the calibration test but nothing happend i could hear the several relays clicking but no movement at all ....before ,seat and mirrors worked in some directions but now nothing...the seat motors are ok and when use the driver seat switch i hear clicks at the ecu but no movement at the seat..when i use the passenger seat switch i hear nothing at the ecu and no movement at all .
any help
 
#19 ·
I wanted to post a follow up on my seat ECU repair on my 1994 LWB. Initially I thought I would try to repair the board with a new battery and chip. Not being comfortable with repairing the corroded circuit board myself I tried to find someone to repair the board. I couldn't really find anyone to take it on or if they did it they wanted hundreds to do so.

So I decided to buy the modified replacement through Proper Parts on Ebay. The replacement is a new circuit board using my case and wiring harness. Took about a 2 weeks between purchasing, sending my unit in, to receiving the replacement. The new board does not keep the memory function but I don't use that in my other car that has it anyway. I might look for a non-memory seat control and use the cover in place of mine to get rid of the memory buttons.

Installed the ECU tonight and am glad to have all the drivers seat and mirror functions again. Cost was about $350 including with postage each way. Certainly more than I wanted to spend but I needed to get it done and I won't have to worry about further corrosion.

John
 
#21 ·
Hey guys, I have a working ECU in my '95 Classic and just ordered a battery replacement (3.6V 150MAH NIMH VARTA) to do some preventative maintenance. I am looking for a good how-to starting from how best to get the ECU out, the battery out and battery back in. I found posts all over place but nothing definitive and clear. Any help is appreciated.
 
#22 ·
Getting it out is easy enough. Unbolt the seat and tilt it back so you can get to the underside. The ECU is held in place by a plastic clip. Release the clip and unplug the assorted connectors. Each one is different so there's no need to mark them, they will only go back one way. The ECU case is held together with self tapping screws so nothing complicated and the top and bottom halves just pull apart to reveal the ECU. Then it gets a little less simple. The battery is soldered in and the board has plated through holes so connection is made to a track on both sides of the board. If you have the experience, a decent soldering iron and a solder sucker, it can be removed without damaging the board but you do need to be very careful. There are tracks under the battery too and it is easy to damage those if you try to lever the battery out. Best way is to cut the pins off the old battery and remove them one at a time. If the ECU is currently working and you aren't going to be repairing tracks, you could even cut the pins off the old battery and simply solder the new battery to those. Before putting it back in (although it might be worth connecting it up and confirming it still works first) give it a good thick coat of varnish.
 
#23 ·
...give it a good thick coat of varnish...
I thought your wife's nail polish was your sealer of choice...;)

On the '95, it's easier than prior years, and the drawing in the RAVE is NOT representative of a '95 RRC. I've had both SWB and LWB, and they both have two large hex bolts on each side of the seat in the rear, (RAVE shows 4 bolts, not two.). Two smaller hex bolts in front just need to be unscrewed, and are harder to reach. I used a hex head socket with a flexible medium extension. Once these are out, the seat will fall backwards, exposing the ECU underneath the seat. If it's never been removed, you may have to clip the zipties holding the various wire harness to the seat frame. Then, disconnect. If the zip ties are not there, it's pretty easy to disconnect. As Gilbert pointed out, each connection is unique and so you don't have to worry about mapping them.

Also, as Gilbert said previously, if you have full functionality, you're probably ok in terms of the various electrical components, but I would still carefully examine the traces, caps, resistors & diodes for any blue/turquoise'ish crystals. Clean that chemically instead of scraping. If it's worse than you want to deal with, there's a forum member, o2batsea, that can rebuild and test the seat ECU for you for a small fee.
 
#25 ·
thanks guys for the help, haven't started yet but before I do...I read that some folks were NOT removing the seat and accessing it from the back. I can see the ECU attached to the top of the seat looking from the back of the driver's seat. Any reason why to remove the seat vs accessing it from the back?
 
#27 ·
For SWBs, definitely unbolt the seat, if you have an LWB, and the forearms of a small child, you may want to attempt removing the seat ECU without unbolting the seat. However, as I stated before, the wiring harness may be zip tied to the seat rails, in which case, disconnecting the ECU from the harness is a real PITA.
 
#29 ·
I'm currently rebuilding my seat ECU on my 95 RRC. I have a question about the ceramic capacitors next to the battery. They have a "104" on them. I bought replacement capacitors with a "104" on them, but they are a little smaller in size than the ones that are on the circuit board. Is that a problem, or are they the same capacity but different physical size? The ones I bought are 100000pF.

Thanks,
Doug
 
#30 ·
...They have a "104" on them. I bought replacement capacitors with a "104" on them, but they are a little smaller in size than the ones that are on the circuit board. Is that a problem, or are they the same capacity but different physical size? The ones I bought are 100000pF.
100000pF = 104uF, so you should be good to go...
 
#32 ·
Great topic!

I have3 RRC's all needing replacement battery's.
To sum up stay away from the NIMH one's? and only get the 100mAH one's not the 150?

Thanks

Guys/Gals
 
#35 ·
For use in the seat ECU, you should be fine with NiMH. I've sourced them from Batteries Plus as well as a few other places on the net. Most of the 3.6V 3-pin Mempacs will be 150mAh, which is fine. I don't think you'll find any in the 100mAh variety, but make sure it's 3.6V, 150mAh.
 
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