Electric Seat ECU

In the last blog, we dealt with the rebuild of the switch pack and warned that if the controls still play up, the ECU would be the probable cause. In my own case, that is exactly what happened.
Before starting, purchase a new 3.5 volt 140 Ma battery – make sure it is one with THREE pins. namely TWO positive and ONE negative.(You can’t buy 100 Ma batteries any longer)
Apart from you usual tools, you will also need fine sandpaper, cheap white vinegar, cotton buds, some tweezers and a small soldering iron (I swear by the gas version – easier to control and no cable to get tangled)

Undo the main battery negative terminal – you do NOT want to fry anything.
The seat ECU is under the RIGHT HAND front seat – accessible from the rear. There are three different units under there and the one we want is the light-coloured box actually attached to the seat base itself. Do NOT mess with the others.
The first objective is to remove the unit from the vehicle. Start by feeling in the gap at between the box and the seat for a “twist” connector. This is usually only finger-tight and requires only a quarter-turn anti-clockwise to release it. Then the box will drop away from the frame.
GENTLY pull the connecting looms back to get better access to the box and connectors. A head-torch helps to see what you are doing in the confined space. Undo each of the multi-plugs – this allows the unit to come further away from the seat so you can see what you are doing.
Now for the worrying bit – with a Philips screwdriver, undo the two screws holding the two halves of the box together. Then ignoring the notice “this voids warranty” peel off the sticker and separate the two halves of the box. You will then see the BACK of the circuit board.
Carefully remove the entire board and wiring looms from the case. Turn it over so you can see the connectors. It is pretty obvious where each loom section plugs into the board but it never hurts to mark each one “A-A” “B-B” etc to avoid any confusion later. When all plugs have been removed, the entire unit will be free to move to the work-bench.

Now you are ready to examine and hopefully fix the unit:

The cause of failure will almost certainly be the leakage of the battery. With luck, it will not have damaged the circuit board beyond repair. With SMALL side-cutters, snip the THREE pins holding the battery to the board. Do this as close as possible to the battery itself leaving as much of each pin attached to the board. Electronic experts will argue about this because they will probably prefer to un-solder the pins from the board but the cutting technique make the positioning and soldering of the replacement battery much easier.
With the battery removed, examine the board carefully. There will probably be a whitish deposit all round where the battery leaked. The deposit may also be on the adjacent components – especially the IC chip and/or a condenser or resistor. These deposits MUST be neutralised.

Using a cotton-bud, swab the area with plain white vinegar – a mild acid that will neutralise the alkaline from the battery. Rinse away the vinegar with water and GENTLY dry the board with air (a hairdryer on low setting is good). Scrape any residual deposits off with very fine sandpaper and blow it clean.
Now examine it again- it will be obvious if the board and/or components are beyond repair. The copper tracks on the board may still look damaged but they can often be cleaned with sandpaper. Do NOT cut into the board – just remove all of the gunk and oxidization. When it is all clean, give it a LIGHT coat of nail polish (Gee, thanks Juliette, I will return it, I promise).
CAREFULLY bend each pin you cut off earlier and position the new battery so all pins are nicely aligned, just touching the battery. (Now you know why you cut them high). Use FINE resin-cored solder to solder each of the three pins to the battery. Examine each joint carefully so ensure you have good joints but no solder anywhere you do not want it.

BEFORE you replace the board into the box, (you can do this after it is back in the vehicle) it is real smart to return it to the vehicle, replace ALL of the plugs, replace the main battery negative terminal and test to see if the seat switches now work. If not, you have either messed something up OR the board/components were damaged beyond saving. However, all you have lost is $20 for the battery and a few hours work. If it all works, SMILE – you have just saved $1000 for a new ECU and several hours of expensive workshop time


This picture shows the refurbished ECU – note the new battery in the top right corner. The wiring plugs have been replaced and the unit is ready for testing.


Remember that a NEW ECU costs around $1000 plus labour. If this procedure is beyond your skill level, at least you now know what is involved and Grahame Cooper Automotive has arranged with this author to do the job for you at a cost of $250 per board, plus postage.
Terms are as follows:
1) A deposit of $125 is required at the time of commencing work
2) The motors must have been hot-wired AND the switch pack must have been tested and/or repaired first to eliminate these items as the causes of the problem
3) When we examine it, If it becomes obvious that the board is damaged beyond repair, there will be NO charge and the deposit will be refunded
4) Even if the seat motors work afterwards, there is NO guarantee the memory functions will work

Please contact Craig (parts@graemecooper.com.au) if you want us to do the work for you

The dreaded electric seat switch

Having recently added a 1993 Vogue SE to my collection, I started to sort out the usual LUCAS mess, beginning with the driver’s seat adjustments (passenger side was OK). Typically, the controls moved the mirrors but not the seat and trying to get a 6’3″ body into the space occupied by the last owner was a challenge – though not as big a challenge as fixing the problem.

Step 1 – remove two screws from the metal cover over the motors and run a jumper wire from the battery direct to the seat motor- just reverse the polarity to change the direction of movement. Now at least the leg room and rake make driving feasible.

Step 2. Undo the NEGATIVE connector on the main battery – this is not essential but it may help you not to fry anything you touch inadvertently.

GENTLY pry off the two levers, then the top plate from the switch box on the side of the seat. If it has one, remove the rubber gasket. Undo the two Philips head screws securing the switch pack to the housing. GENTLY prise out the pack and unplug it from the loom.

Take the pack to a CLEAN area and place it onto a towel or other surface where the contents will not be lost for ever, Turn over the unit and remove the single Philips head screw from the underside. Then take Valium or strong drink to fortify yourself against the inevitable moment when most of the ball bearings and springs decide to remove themselves from their dedicated location.  GENTLY prise off the cover – Now you know why you are working on the towel. 

Take a very good look at where everything (is supposed to) fit and make sketches if necessary. Carefully remove all of the posts and their brass pins, also all brass contact plates, springs and ball bearings. Clean everything with electrical cleaning fluid and rub the brass strips with FINE sandpaper until everything is shiny.

Replace all strips into their little sockets- keep them clean – NO grease yet.  Replace each of the brass pins and GENTLY replace each post into its socket,  Do NOT damage the plastic housings,  It is very obvious where each one goes (you DID make a sketch didn’t you?). Then hold each ball bearing with forceps (borrow your partner’s eyebrow tweezers if necessary) and dunk each one into a tub of Vaseline until it is liberally covered and sticky, One hole at a time, drop in ONE ball bearing, followed by one spring. (That way you know which holes have the bottom ball bearings refitted).

Now for the tricky bit! One ball bearing at a time, dunk each into the Vaseline and sit it on top of a spring – the gunk will keep it in place – you hope.

GENTLY align the slots in the cover plate with the control posts and lower it until it snaps into place. Hold it down and give it a little shake – you should NOT hear any balls rattling around,  If you do, remove the cover and try re-seating the balls and/or springs again.. Do not replace the bottom screw until you are sure you have got is all right. If necessary, take more Vallium and/or strong drink and persist.

Finally, replace the switch pack into the seat housing, replace the main battery lead, start the vehicle and try the seat switches. If the seat now adjusts correctly, take more strong drink because you have (probably) fixed the problem. If only the mirrors move but not the seat, the problem is in the seat ECU and fixing that will be the subject of a different post.

 Be comforted by the knowledge that this first I did this it took me half a day – now I can do the entire job in less than an hour.

DIY petrol engine repairs

Ever tried rebuilding a land Rover petrol engine – say the 3.5 or 3.9 version? Yes it can be done by anyone reasonably handy but there are many tricks and traps in the process. Here is an excerpt from the full article that appears on the Graeme Cooper website – just one of many articles at http://www.graemecooper.com.au/articles.htm

If you think you can save money by rebuilding your own engine – good luck! Unless you have a) done this before and/or have fairly extensive mechanical experience b) comprehensive variety of workshop tools, c) a workshop manual and d) heaps of patience, you will soon come to realise that what seems like too much money to pay a professional workshop is actually the cheapest and most efficient solution.

One major reason the professional cost seems high is that the work is warranted, meaning if the job is botched, it will be redone at the shop’s expense. Second hand or after-market parts will also not be used unless they are from a known and proven source.  Also, even existing components will be inspected by someone who knows what to look for and anything suspect will be replaced or repaired. Here are some examples:

  • Cylinder heads may be warped or have gone soft from heat over a long period. Unless they are tested and if necessary straightened at a cost of up to $1500 a pair, they are effectively worthless.
  • Stripped threads will prevent bolts being refitted to the specified torque, so coolant, oil and/or compression leakage is inevitable. The professional shop may be able to fit helicoils or re-tap the threads – not something most home mechanics can do.
  • Reuse of gaskets is false economy – replacements may add a few hundred dollars to the price of the job but this is unavoidable for a successful result

The same applies to many of the hoses, especially those that are hard to access

LPG for a Range Rover Vogue

Graeme Cooper Automotive does not experiment on customer vehicles! Stuart has acquired a fine LM Vogue that will shortly be converted to dual fuel. This will eliminate any installation issues and make a similar job for a customer “bulletproof”

GCA have already installed dual fuel systems on many other vehicles, including Discoveries and P38 Range Rovers