1997... BCM Maybe?

ok... I have read a ton of these BCM problems.. It sounds like my problem but let me list AND add another at the end:

- Wipers like to do a mystery swipe when I start the car
- dash lights flickered but when I replaced the alt and battery it stopped
- radio?
- security system.. alarm ... remote door lock ... does not work
- periodically the security system just clicks (click like a second hand... click...click...click) and I only think it is the security system...

now, the car out of the blue just decided to die... interior lights decided to not work, car will not start, appears dead.

My symptom... A ton of clicking under the dash. Tall relay on the fuse block under the dash clicks maddly (i need to find a pic of that block to see what that relay controls). When I turn on the hazzard lights is when it happens.

Could it (the BCM) also control my tranny? That appears to skip some times.

I dont want to start replacing parts.. becomes expensive. What do you all think?

Thanks!

Problems with erratic symptoms could be a voltage supply problem. An intermittent ground at the battery or alternator could cause it. Try using a jumper cable on the battery negative terminal and connect it to a good chassis ground. Also use the remaing jumper cable and connect the alternator case to the negative terminal of the battery.

Does that get rid of the prob? If yes, then clean up the ground connections on the battery, and alternator.

Try the same process but now connecting the postive side of the battery to the power distribution point. (To find the distribution point, just follow the red battery cable along till it reaches the distribution point.)

Also connect the positive output from the alternator to the postive battery terminal.

If the problem appears when yo do this, clean the +12 volt connections on those cables and tighten well.

Do not try to test for poor connections using an Ohmmeter. When the system is not under load, a poor connection can show up as a good connection using an Ohmmeter.

Good luck

WOW... I have to admit... this forum has been a wealth of information.

Recently I replaced the battery AND the alt. I will check those connections and see if it works. Fingers crossed!

THANKS!

I tried it... no go.

I disconnected the neg cable... put it back on and it appeared to be fine. Then it started up again (the problems.. not the car). I am going to remove the battery and look at everything under and all around.

Symptoms...

relays under the dash appear to be going wild.. possessed!
Headlight relays under the hood doing the same.
black box under the dash.. I think the alarm.. goes tick..tock.. tick.. tock. I would remove it... would probably totally screw everything up.

What did I do recently? I replaced the alt AND the battery. I will dig and check the connection to the alt.

Question: If the connection to the alt is simply loose... will that cause this? (I am sure I will get some responses telling me "maybe").

Question: Could it be a simple battery problem? can the battery be bad?

THE BCM... can it be tested? I dont want to replace a $200 part to find out it was not that!

HELP!

and thanks!

A loose connection can give you voltage spikes or electrcial noise, It appears that the problem went away for a while when you replaced the alternator. It is possible that with the moving in of the new alternator, a connection got cleaned or possibly the cable was positoined in such a way that a faulty connectin was good for a while.

Try jiggling the battery cable to the alternator and have someone watch for symptoms.

Good luck

make sure you have good voltage from the battery when your trying to start the van volts should stay above 11 volts on a crank if too low you may have a defective battery would'nt be the first time i seen that

I will check all the connections. As you all know, it is not easy to get to the Alt. As for the battery.. I guess I am just skeptical that it is the battery... but a friend also said the same thing.

Thanks and I will check in tomorrow

shoot... forgot about this post and posted a new one. well.. here is a sypmtom.... Starter sounds like a machine gun. I thought it was that and replaced it... Stupid shade-tree mechanic I am. I think I am going to tear down the Alt again and check all the connections. Just so hard to get to.

From what I have learned and what people tell me it has to be a bad ground somewhere.... With the new symptom (the alt machine gun) does anyone have a good suggestion where to start other than the Alt?

Thanks!

HI

It is usually either a bad ground or a bad power connection. Before you do any diagnosis, make sure the battery has enough charge to start the vehicle and clean the terminals and clamps on the battery and tighten them.

Test the ground connection
To test for a faulty ground connection, place the negative probe of the voltmeter to the negative terminal (not the clamp) and the positive probe to a good electrical point on the engine block. Turn the headlights, rear window defrost and blower motor at full speed on. The voltmeter should measure close to 0 volts. Definately below one volt.

Now turn off the headlights, blower and defrost. Have a mate turn the ignition key to start while you measure the voltage between the negative terminal and engine block. The meter should be reading close to zero.

If the meter jumps from 0 to a over a volt or stays over a volt, the connection from the negative terminal to chassis ground is faulty.

To diagnose a faulty ground connection, measure from the negative terminal to the clamp on the same negative terminal. The voltage between those to points should be vey close to 0. I it is not, the terminal and clamp need to be cleaned and tightened. If the voltage was close to 0 and you determined in prior steps that the is a fault with the ground, connect a jumper cable form the negative terminal clamp to a good point on the engine block and start the car. The car should start if the procedure was followed from the beginning to this point. Should the car not start, try getting a better ground connection on the engine block.

Testing the +12 volt cable to the starter
Connect the positive lead of the voltmeter to the +12 volt terminal (not the clamp) of the battery. Connect the negative lead of the meter to the starter motor post where the battery cable connects to the starter. (You need to get under the vehicle to do that but don't stay down there when someone is starting the engine, bad things can happen.) Use an aligator lead and connect one end of the lead to the post on the starter and the other end to the voltmeter lead. Have a mate turn the key to start and watch the meter. The meter should be reading close to 0 volts, definately less than 1 volt. If it the voltage reading is too high, replace the starter motor cable. If this test proved okay, then the problem is with the wiring from the ignition swtich to the startrelay voltage at the starter.

Good luck

Teakstone

Thank you for your response Teakstone... I will try those tests. I am resolved to taking it to a mechanic tonight if I can not find the problem. Unfortunately, I need the car. Fingers are crossed that your test will further help me out!

I will post what the mechanic finds.