Crazy electrical problem

[BgEoEdR]

When i start my car sometimes the greeting under the speedo/tach doesnt appear but the door buzzer/dingdinger keeps going off and the back light behind the screen will come on when i press the brake and turn off when i let go . if i punch it in neutral or 1st when the tach goes a little past 4grand the greeting will pop on and i can recall the obc values that have programed whereas before i hit 4k i get nothing from the dash display for the obc.
Anything guys ive got no clue, i was kinda thinking that maybe the electrical system was not holding enough watts/amps/chargeinbattery and then when i excede 4grand the alternator is pumpin enough juice to get it going but i dont know it dont effect driveability so im not trippin but it kinda drives me nuts

[winfred]

i was told about a tsb (technical service bulleten) that was on the subject of weird cluster power activity and the root problem was a defective aux water pump for the heater, it's below the heater valves next to the fusebox, i think unplugging the pump should tell if it's the cause if the problem goes away

[BgEoEdR]

Its sounds kinda out there, and I dont know what the pump looks like but i will go out and look tomarrow. if that is the problem,the solution would be a simple replacement of the pump(how simple is this stuff ever really)? Thank you very much.

Any body else reading this if youve got other ideas as to what it could be any input is appreceated.

[winfred]

it's only about 20% ******** as the tsb is from bmw, heres a pic of the pump and heater valves, it's # 1
http://members.cox.net/wdixon27/aux%20pump.jpg

[Bill R.]

his though, usually i see this when the capacitors in the dash cluster have gone bad. One of the first symptoms is as soon as you hit the break pedal the chime goes off. And then once you raise the rpm up aways everything goes back to normal.. The trip odometer usually resets itself back to zero also... I think that the bad capacitors in the dash won't hold a charge like they are supposed to, so when you start it up everything resets since it lost memory power and when you rev the engine up the alternator puts out enough that the dash capacitors get charged back up after a few seconds.
http://www.bimmernut.com/%7Ebillr/images/auxiliarypumpdiode.jpg









i was told about a tsb (technical service bulleten) that was on the subject of weird cluster power activity and the root problem was a defective aux water pump for the heater, it's below the heater valves next to the fusebox, i think unplugging the pump should tell if it's the cause if the problem goes away

[winfred]

i have a customer with a early e32 that has a problem sorta like he describes and it's whipped almost every bimmer shop in town, i've swapped damn near everything without effecting it, went over it with a fine tooth comb when i did a heater core last year and had the dash gutted, we came across this tsb about a month ago and fixed a early 750il with it, haven't had a chance to try it on alex's car as it's not returned for service yet and he just ignores it



his though, usually i see this when the capacitors in the dash cluster have gone bad. One of the first symptoms is as soon as you hit the break pedal the chime goes off. And then once you raise the rpm up aways everything goes back to normal.. The trip odometer usually resets itself back to zero also... I think that the bad capacitors in the dash won't hold a charge like they are supposed to, so when you start it up everything resets since it lost memory power and when you rev the engine up the alternator puts out enough that the dash capacitors get charged back up after a few seconds.

[Bill R.]

just fine..







i have a customer with a early e32 that has a problem sorta like he describes and it's whipped almost every bimmer shop in town, i've swapped damn near everything without effecting it, went over it with a fine tooth comb when i did a heater core last year and had the dash gutted, we came across this tsb about a month ago and fixed a early 750il with it, haven't had a chance to try it on alex's car as it's not returned for service yet and he just ignores it

[winfred]

we've had several different clusters in it with no change, about the only thing that hasn't been swapped is the body harness


just fine..

[Scott E]

A while back my LCD cluster stopped working all together. I ended up replacing it with another used cluster which has been fine except for the trip meter resetting when I start the car. Lately there are times the LCD display stops working and shutting the car off, then back on usually fixes it. Other than the trip meter resetting and the LCD panel not displaying I dont have any of the other symptoms of capacitor failure (which still could be the problem).

Also my heater works marginal at best. Unless the car is moving and the driver's dial all the way to the left I am lucky to get any heat.

I wonder if my aux water pump is faulty thus causing these problems? I have cleaned the heater valves but I suspect I really should replace both the heater valves and aux water pump. (been telling myself next winter for 3 years now). Since I live in SoCal having a heater isnt a priority.

Thanks for the TSB info (that goes for you too Bill R)

[bimmerd00d]

my aux pump randomly started functioning this year, about the only good thing about my car :D

[Scott C]

Amazing how screwy these clusters get. I had a false trans failure that kicked the snot out of the dealer for 3 or more months (can't remember now).
They... swapped out the cluster board with a new one (800$) - did not fix.
Swapped out with a "loaner", did not fix the problem AND the loaner now had the false tranny failure problem!
They resistance (and short) checked all wires going from tranny to CCM.
They took tranny apart to check harness
Ultimately, I lost patience and took the car back and then grounded the tranny control unit signal (cut wire from tranny) into the CCM to "mask" the real issue. During this time (last few years), I still get random resets of the cluster (and this is with the "new" board). The odometer module was NOT replaced but was swapped with another one I bought.

So with all that seemingly not related history, I am wondering if the odometer module (cant remember its real name) gets corrupt on these cars and then causes these problems - is there a way to reprogram these or maybe swap with another?

Scott

[winfred]

the chip that contains the mileage can be swapped out and i've found usually doesn't set the tamper dot in the display, it's on the back of the cluster with a small plastic surround that i just break off and pop the chip out.

ps alex's e32 still has it's screwy cluster after all of this time and he still ignores it

[Gearhead]

Guys, I'm doing some serious scouring of these posts before I start a new thread concerning the issues I'm now having. On this topic, let me ask: Is it possible for an instrument cluster or CCM failure to cause a no-start problem? In short, is there anything the DME or EWSII looks at from the CCM/Cluster that would prevent cranking intermittently?

The issue I'm dealing with is far deeper than this, but I'm trying to find a good place to start.

Thank you!

[Scott C]

I am pretty sure I saw the mechanic start the car with out the CCM. Not sure about the cluster.... I don't have an SRS reset tool which you will surely need after turning key to On with airbag off (to get cluster out).

Scott

[genphreak]

No way. EWSII is too basic.

Check that your wiring under the back seat is not corroded underneath the rear power distribution box (the EWS shocksensor is mounted on the rear seat frame and shares the same harness).

If you cannot find root cause, make sure you have enough voltage (ie well charged battery reading above 12.5V), and have checked crank and cam sensor outputs are reading good values.

You may be able to bypass the EWS using a 12V feed with a 30A switch connected to it. Connect the switched output to the starter motor wire that would normally run to the EWS unit under near column to the run the starter motor. You will need to use the key AND the starter button at the same time, one enables the ECU/fuel (EWS), the other powers the starter motor solenoid.