[soxfan]

My '01 T&C (w/ 3.8L) suddenly fails to start. Won't even crank over. I thought it was the battery (battery was 3 mo. old, but took back to store and they said it had a dead cell). Put new battery in, still wouln't crank. Next logical thought is the starter. Fought to replace the starter today (boy that top bolt is a pain). Got the new starter in, and still won't crank over. All dash lights work. Everything electrically seems to work other than getting the starter to crank. I even swapped out some of the relays right next to the battery, thinking it may be a bad relay, but no change. Anyone else see this? Anyone have any ideas where to go next? Thanks in advance.

Richard

 

[RIP]

Smack the dash above the instruments. If it comes to life you may have bad solder joints on the instrument cluster circuit board. The PCI multyplex data bus is used by all the computers/modules as a communications conduit. If it opens anywhere, depending on the fail mode, you may not be able to start. The instrument cluster is a common fail point. If it cranks, you probably found the culprit.

A multimeter could have saved you some work. Pull the starter relay and check for 12vdc at contact 86 on the relay socket with the key to start. If it's there, voltage is making it from the battery to the ignition switch through the transaxle range sensor and on the the starter relay. Your problem would then be either the relay, starter, or the connecting wiring. If the voltage wasn't there, you're looking at the previously mentioned components and their wiring.

One caviot. The relay needs a ground at contact 85. That comes from the powertrain control module better known as the PCM. The health of solid state electronics are very suseptable to voltage spikes and current veriations. Worst case scenerio would be the fried battery cell may have effected the PCM.

 

[soxfan]

I did see posts about the dash issue, tried smacking it a few times, didn't make it start. Is it possible that it still is the solder issue in the dash?

I did check the voltage at the starter; disconnected the plug (postive wire, right?) from the starter, stuck one lead in there and put the other lead on the bolted on wire (assuming thats the negative). Had my wife try to start it, got 0 volts at that point, so am assuming that it means something isn't sending power to there.

When I pull the starter relay, to check voltage, which ones are contacts 85 & 86?

 

[JCamasto]

How many miles on van? Owners?

I'm guessing ignition switch or relay... (Maybe trans interlock?)

-Jim

 

[RIP]

I did see posts about the dash issue, tried smacking it a few times, didn't make it start. Is it possible that it still is the solder issue in the dash?

I did check the voltage at the starter; disconnected the plug (postive wire, right?) from the starter, stuck one lead in there and put the other lead on the bolted on wire (assuming thats the negative). Had my wife try to start it, got 0 volts at that point, so am assuming that it means something isn't sending power to there.

When I pull the starter relay, to check voltage, which ones are contacts 85 & 86?

Yes, could still be a solder issue. It's not a sure fire test, only an indicator. The only way to know for sure is to have a look see.

Well...no...here's how I would check starter voltages. There's two connections on the starter. One for primary voltage from the battery to the starter motor windings (larger diameter wire). The other is the input to the starter solenoid switch from the starter relay (smaller diameter wire). With the key off touch the positive meter lead to the primary connection and the negative meter lead to the engine block or any heavy metal attached to the engine (ground). You should see 12 vdc. That voltage is there all the time. Now connect the leads in the same way except to the solenoid connection. Turn the key to start. You should now see 12 vdc. If those voltages are there and the connections are clean and tight, the starter is bad. FYI - generally, if a starter is having a problem, it's the starter solenoid contacts and plunger that need to be replaced. Little else fails in a starter. The contacts can be changed for about half the price of a new starter. You can buy a kit for around $25 and do it yourself. All this is water over the dam since you have changed the starter but, might need it for another day.

You should see the contact numbers on the bottom of the relay.

You've got a ways to go before you get to this but, if it turns out to be the PCM, it has an 8 year or 80,000 miles emissions warranty on it. Might not cost you a cent.

 

[soxfan]

How many miles on van? Owners?

I'm guessing ignition switch or relay... (Maybe trans interlock?)

-Jim

About 80K for milage and I bought it used in 2004, so not sure if I am second or 3rd owner.

Wouldn't switching the relay rule that out?

 

[soxfan]

Yes, could still be a solder issue. It's not a sure fire test, only an indicator. The only way to know for sure is to have a look see.

Well...no...here's how I would check starter voltages. There's two connections on the starter. One for primary voltage from the battery to the starter motor windings (larger diameter wire). The other is the input to the starter solenoid switch from the starter relay (smaller diameter wire). With the key off touch the positive meter lead to the primary connection and the negative meter lead to the engine block or any heavy metal attached to the engine (ground). You should see 12 vdc. That voltage is there all the time. Now connect the leads in the same way except to the solenoid connection. Turn the key to start. You should now see 12 vdc. If those voltages are there and the connections are clean and tight, the starter is bad. FYI - generally, if a starter is having a problem, it's the starter solenoid contacts and plunger that need to be replaced. Little else fails in a starter. The contacts can be changed for about half the price of a new starter. You can buy a kit for around $25 and do it yourself. All this is water over the dam since you have changed the starter but, might need it for another day.

You should see the contact numbers on the bottom of the relay.

You've got a ways to go before you get to this but, if it turns out to be the PCM, it has an 8 year or 80,000 miles emissions warranty on it. Might not cost you a cent.

Will try and get the voltages from the relay connectors and recheck the voltage at the starter. Thanks for your help.

 

[soxfan]

A multimeter could have saved you some work. Pull the starter relay and check for 12vdc at contact 86 on the relay socket with the key to start. If it's there, voltage is making it from the battery to the ignition switch through the transaxle range sensor and on the the starter relay. Your problem would then be either the relay, starter, or the connecting wiring. If the voltage wasn't there, you're looking at the previously mentioned components and their wiring.

One caviot. The relay needs a ground at contact 85. That comes from the powertrain control module better known as the PCM. The health of solid state electronics are very suseptable to voltage spikes and current veriations. Worst case scenerio would be the fried battery cell may have effected the PCM.

Ok, here is what I got with the meter:
contact 86: 12.4V from the contact to positive terminal on battery (without having key to start)
contact 85: 12.0V from the contact to positive terminal on battery (without having key to start)

I checked resistance from terminal 85 to 86 on the relay. Got about 75 ohms across them. (not sure if that means anything, I pulled the relay right behind it and got the same reading).
Also, when turning the key to start, heard clicking from the relay box, so does that mean there is power getting to there?

 

[soxfan]

Latest update....

1. Re-checked all my electrical connections and voltages

2. Have 12Vdc at starter large diameter wire

3. Have 0Vdc at solenoid wire (small diameter wire at starter) with key to start

4. At relay prong 86, have 12Vdc (from prong hole to battery ground) with key to start.

My assumption:
The wire from starter relay to the starter solenoid is "bad".

Assuming that the wire didn't come off the bottom of the relay box, or it's not severly corroded:
Is it a direct connection?
Can I just replace the wire (if so, which one actually is it that connects to the relay?)

Lastly, how do I get to the wires under the relay box?

Thanks for all the help!

 

[RIP]

Latest update....

1. Re-checked all my electrical connections and voltages

2. Have 12Vdc at starter large diameter wire

3. Have 0Vdc at solenoid wire (small diameter wire at starter) with key to start

4. At relay prong 86, have 12Vdc (from prong hole to battery ground) with key to start.

My assumption:
The wire from starter relay to the starter solenoid is "bad".

Assuming that the wire didn't come off the bottom of the relay box, or it's not severly corroded:
Is it a direct connection?
Can I just replace the wire (if so, which one actually is it that connects to the relay?)

Lastly, how do I get to the wires under the relay box?

Thanks for all the help!

No you can't assume that yet. 3 things have to happen before you get voltage at the solenoid connection at the starter. 1) There has to be 12 vdc to the relay coil. You proved you're getting that at contact 86 on the relay socket. 2) There has to be 12vdc waiting at the power side of the switch contacts in the relay. Check for 12vdc at contact 30 on the relay socket. That voltage should be there all the time. It comes from the battery then through a 40 amp fuse #9 then on to the switch contact. 3) The relay coil has to be energised. For that to happen you have to have power at contact 86 (it's there) and a ground to the relay coil supplied by the PCM. Here's where I'm fuzzy. The ground is switched on by the PCM, but what is the PCM looking for to switch the ground on?

I can guess and say the PCM is looking for an input from the securtity system start immobilzer telling it all is well or the Transaxle Range Sensor (TRS) telling the PCM the van is in park or neutral. Maybe someone can fill in that blank. In any case, you could try disconnecting the negative battery lead for a few minutes to reset the security system or jiggle the gearshift to reset the TRS.

If all this is turning to mud, a picture might help. This link will get you there: http://www.oplin.org/databases/proxy2/proxy.php?qurl=http://arrc.epnet.com/autoasp/framerq.asp Takes a bit to get to the diagram:

Type 123456789 in the password block
Scroll to Cincinatti library and click submitt (give it time to load)
Scroll to ARRC
Select 2001 then Dodge Grand Caravan to get diagrams (applies to T&Cs)
Select wiring diagrams then starting system

Everything I've talked about is based on this diagram. It's a simple diagram, unfortuneately, it doesn't tell us everything we need to know. If you draw a line from the middle top of the diagram to the middle bottom, it should bisect the starter relay. Looking at it this way everything to the left of the line energises the relay coil and everything to the right works as the result of the coil being energised.

 

[soxfan]

Thanks again RIP...

Ok, here's what I think:
I went out at night with my handy dandy super bright mag-light to check the voltage at contact 30. Nothing...dead. So, I am looking around and remembered the fuse from the drawing and what you referred to. I look at the underside of the relay box cover to try and find fuse 9. None marked 9...go figure. So, I start really looking hard at the 40A fuses in the box. Notice one looks a bit odd, but not enough that it would have (or ever did) look odd without a super bright light shining in it. I pulled it, brought it in the house, popped off the cap and right under where the "40" is written, the copper ring is melted!!!

So, on the way home from work tomorrow, I am stopping at the parts store and hope they have some of these funky fuses. If that's all it is, I will be so happy. Will let you know tomorrow!

 

[RIP]

Sure hope that's it. Do they ID the fuse somehow?

 

[soxfan]

So....not the fuse. Replaced it. I have power at contact 30 now though. Still considering the idea of a bad wire....Going to check the voltage at the plug after dinner.

UGH!

 

[soxfan]

Checked the voltage at the plug on the starter. Still no power there. Only thing I can think is that what ever is supposed to give the ground (TPS???) via contact 85(?) isn't supplying the ground??? Either that, or the wire from contact 87 to the plug on the solenoid is broken somewhere.
It sounds like the relay is "clicking" when taking the key to start, but not sure. Tomorrow, I will double check that.

Anyone have any ideas why no power to solenoid?

 

[soxfan]

bump back to top

 

[soxfan]

I jumpered across pins 30 & 87 in the Engine starter motor relay and did get power to the solenoid doing that. So, that leaves the question, why isn’t the relay causing the “switch” between 30 & 87 to shut? I have power at pin 86 with the key to start. So, whatever is supposed to complete the circuit at pin 85 appears to be the problem. It shows it going to the “double start override” in the powertrain control module, just not sure what that is or how to correct the problem.

 

[soxfan]

Ok, I have verified there is NO ground present with key to start at contact 85. Anyone have any ideas why this would be? Something is supposed to tell the "computer" (powertrain control module) to provide ground there (right?), but I have positive 12vDC there.

 

[RIP]

Ok, I have verified there is NO ground present with key to start at contact 85. Anyone have any ideas why this would be? Something is supposed to tell the "computer" (powertrain control module) to provide ground there (right?), but I have positive 12vDC there.

Shoot your question to this guy. His user name on this (I think) and other forums is RickMN. He is a retired certified mechanic with years of experience. The link is to his blog. Make sure you ask him specifically what turns on the ground in the PCM. http://free-auto-repair-advice.blogspot.com/

There is every chance the PCM is bad but, there's that nagging question to clear up. Hopefully RickMN can shed some light.

 

[soxfan]

RIP, thanks, I emailed him and am waiting for his response.

If anyone else has any suggestions, please let me know.

 

[soxfan]

Still trying to find the problem. I am having to fight the weather, it's been rainy here the last week or so. If anyone has any other suggestions, please let me know.

I did get a suggestion to check the TPS & CMP to verify they have proper voltage. So far, I did check the TPS, it has 5volts. Anyone have a good description of where the camshaft position indicator is? I need to verify it has proper power. (if not, that could prevent the ground signal from the PCM to the start relay)