no power no nothing to whole car

[3toedshewie]

idea!

Here is how I hooked up the battery wrong.
positive lead from charger on negative terminal of battery
negative lead from charger on engine block.
charged at 2 amps. it was that way for 1 minute.
so maybe I need to check every ground to see if thats the problem?
is this a good idea? or am I just wasting my time?
Is it possible to knock out a ground?

and do you think its safe to put another ecm on right now?
what else do you think I may have knocked out?
any guesses?:-D

[3toedshewie]

I just checked voltage using the "diagnostic connector" to pins:
18-ecm voltage= 0.00 volts
19/20-ecm transmit and recieve = 0.00

also found a little plastic box on the harness leading to the computer. cracked it open-a small electric component, looks like a diode (black can/silver stripe on one end with two in and out leads.) tested voltage 3 volts. anyone know what this does? is this to protect the ecm?

[DaveSmed]

The terminals of the diagnostic connector really aren't too useful for voltage tests, they are used with an ancient scan tool.


That incorrect connection should have been hard on the grounds in the car between the battery and the engine block, BUT those grounds are also sized to handle the amperage from the starter, the 2A breaker in the battery charger should have been the weak point there. I wouldn't immediately suspect it to look for a ground through the DME, but it is possible.

Now when you checked C100, did you ground the meter to something like the hood hinge bracket or the battery -ve?

See if you can find that aux fuse box, you are correct about it being a fuse box with no fuses, its a provision for installation of aftermarket accessories. One terminal is constant 12v, one is switched.

Turn the key on and make sure both have 12v+, that will check and see if the green wire from the ignition switch is getting power.

[3toedshewie]

Hey Davesmead,

good to know about the diagnostic connector, thank you, will not rely on it for accurate voltage measurments and tests.

ok, will not go too crazy on the grounds.

When I checked C100 voltage I connected the negative lead of the voltmeter to the ground that the negative lead of the battery is connected to, the one closest on the shock tower.

I will check to see if the two contacts in the aux fusebox have 12V like you suggested with the key on.

I want to understand what you said about the grounds being damaged more. You said "I wouldn't immediately suspect it to look for a ground through the DME, but it is possible." could you clarify that more, not sure what you mean by "look for a ground through the DME."

found out a usefull tip for anyone going to try to diagnose a similar problem. When using a mulitmeter to test to see if a diode is good or bad, dont use a voltage drop test. there is a selection on the dial that looks like an arrow hitting a wall. use that. put one lead of the multimeter on one lead of the diode and one multimeter lead on the other lead of the diode, order doesnt matter, hold the leads for 5 seconds like that. the multimeter will then display "good" if it is good and nothing if it is bad. doesnt matter which lead goes on which side of the diode.

[DaveSmed]

Which diode are you checking? Can you take a pic?

When you connected the +ve lead to the -ve terminal of the battery, and the -ve to the engine block, you created a short across the charger through the ground circuit in the car. The current should have gone through the terminal, the ground strap to the shock tower, the chassis of the car, the frame rail-oil pan ground strap, the block, and finally the bracket. (in a perfect world)

2 amps wouldn't phase that "circuit", it handles all the current from the starter.

The DME also has a ground connection at the shock tower, and a bunch of wires and ancillaries on the engine. Conceivably the current could have sought a path through the DME as well, which wouldn't take the 2 amps without major damage.

That said, that's just the DME. The rest of the crap on the chassis of the car should work normally. Given some of the stuff that's not working, it sounds like the ignition switch is not working properly (like the headlights), possibly failing to energize the green wire that powers a bunch of stuff (incl. the DME)

I would try to get the rest of the stuff working and have a good foundation before trying to screw with the computer.

[3toedshewie]

troubleshooting in the rain

yes, there is 12 v going to one of those fuse sockets but not to the other one with the key in the ignition and in first position. sweet. so now I am going to check for a bad igntion switch. to the bentley!

Thank you. Thank you dave. I have a new starting point.

oh and wierd thing happend. my sterreo just powered on for the first time since the incident. maybe its the rain?

[3toedshewie]

picture of that diode for those curious

here it is chillin with my ecu in the glovebox

[3toedshewie]

Update

Looks like I gotta keep lookin.

tested the ignition switch today after finally getting the steering wheel off.

Ignition switch passed all the tests that were in the bentley. word of note. its a b$%Ih getting the connectors to make correct contact with the multimeter test leads when doing a continunity test.

I suggest when performing the tests for the ignition switch in the bentley that you first make sure you have correct contact with your first contact to test.
here is how: check for contuniuty across the connector for the same wire first. i.e. connect one test lead to the black wire on one side of the connector then connecting the other test lead to the other side of the connector. if it beeps you know are getting a good connection between the first test lead and the connector wire you are testing.

so I am going to now figure out why there is not power going to that green wire that goes to the auxillary fuse box .

then I am going to start checking for shorts with a incandesent test light hooked up each fuse in the fusebox.

after that maybe the starter. damn, I was hoping it was just the ignition switch.

any advice is more than welcome.

one more note. the etm is not entirely accurate as to wire colors, there is a second violet wire that goes to the connector in the bentley and in the etm. but I could only find a grn/wt wire in the connector postion the violet wire should be. that is not encouraging.

[3toedshewie]

Update

I have started the process of checking to see what is getting power.
I started with the computer. if power goes in, great. if power goes out, great. lets have a look.

not sure what is power in and out in computer so I started checking all the power to ground combos I could find in the ETM. took off the back of the ecm connector ( removed three screws, removed the rubber gasket that seals the connector to the ecm, and the wire wrap on the harness conneced to the connector, after that the connector for the ecm pulls right out.)

I checked:
1) ecm connector 18 (little red wire) to ecm 19 (big brown wire) - 12 V, is this power in or out?
2) ecm 18 to ecm 2 - 12 V, in or out?
3) ecm 18 to ecm 14 - 12 V, in or out?
4) ecm 18 to ecm 24 - 12 V, in or out?

oh and more importantly- what is a good way to check for a bad ground?
incandesent test light? multimeter? led test light? continutity? voltage drop? any real good tests?

-shewie

[3toedshewie]

That said, that's just the DME. The rest of the crap on the chassis of the car should work normally. Given some of the stuff that's not working, it sounds like the ignition switch is not working properly (like the headlights), possibly failing to energize the green wire that powers a bunch of stuff (incl. the DME)

I would try to get the rest of the stuff working and have a good foundation before trying to screw with the computer.

tonight I am going to start with what you suggested. going to find out why that green wire leading to the aux fuse box is not getting power. and to see if I am getting power to the ignition switch. what circiuit is that green wire on? Is it the thick solid green one leading out of c200?

going hunting.

[3toedshewie]

Its alive!!!!!!

started to test if everything had power. hooked the battery back up. put the key in the ignition.....wait.....everything is on.......WTF! YES!!!
ok. calm down. is power going to aux fuse box "ignition position" fuse socket?....CHECK
Is power going to starter?.....CHECK.

Lets try to start it!

it starts! yes!!! happy dance. I think in testing the ignition switch connector last night I pushed in the main red wire (c200-9) trying to get connectivity on either end of the connector. did not get connectivity at first... pushed it in, got connectivity. good. never hooked up the battery to test it last night... saved that for tonight.

In conclusion I beleve the loose main red wire in C200 on the ignition switch side was the culprit. thank you everyone who submitted a reply. I am going to keep my eye on this problem because I am still not sure why its running.

[StereoInstaller1]

If your parking lights come on but no dash lights, your switch is bad most likely.

have you downlaoded the ETM yet? It is far more comprehensive than the Bentley

[3toedshewie]

thanks.
yes. the etm is alot more comprehensive....and usefull....if you can read it. Im a noob. I am still learning how to use it.
My headlights are coming on now, thanks, not sure if its the switch or not. do you know how to replace the ignition switch without having to use a new key for the new switch?

[StereoInstaller1]

The electrical part of the switch is separate from the key part... and there is a part in the middle that screws up too.

[3toedshewie]

Thanks. going to the junkyard for a spare.