Why wont my van start?

If that's a rather loud clunk once each time you turn the ignition switch to "crank", that's commonly caused by worn solenoid contacts inside the starter. They can be replaced for 20 bucks but most people just replace the entire starter. Since you already did that, the next most likely suspect is the battery cable going to the starter or the negative cable that's bolted to the engine. If you installed a used starter, it could have worn solenoid contacts too. That's a real common problem.

You'll need a test light or voltmeter, and a helper to diagnose the problem. If that click you're hearing is real light, you might be hearing one of the many relays that turn on and off during cranking. First you have to determine if the starter relay is clicking. If it is not, the neutral safety switch is the logical suspect. It's built into the "PRINDL" switch. That runs the shifter indicator on the dash.

Dandy. The next thing to do is measure the voltage on the smaller wire on the starter. You should see 0 volts until your helper turns the ignition switch to "crank", then you should find around 12 volts. You should hear the solenoid engage too. Let me know what you find.

Wonderful news. Don't feel too bad about buying the starter. It is a common failure item, even though it has an easy fix, so now you won't have to worry about it for a few years. Everyone who suggested it was defective would normally have been right. Corroded battery cables and clamps are much less common but they can cause similar symptoms.

My daily driver is a rusty trusty '88 Grand Caravan. It had a different style starter, but I installed that little silver Nippendenso starter on it many years ago after a student accidentally broke the original one. It bolted right up and has been working fine but I have a spare replacement ready to go when needed.

Just so you're aware, when those solenoid contacts become worn, you'll get one loud clunk from it each time you turn the ignition switch to "crank", but it won't spin the engine, however, it WILL work if you cycle the switch a few times. One of the parts that wears turns a little each time you release the switch. When a good spot comes around, it will crank the engine. That can go on for months. It won't suddenly let you sit. When that happened on my ******'s '95 Grand Caravan, I ignored it for so long, one day she lost count after 700 attempts and a blister on her thumb, but it did finally start. As I recall, on your van, you can only try it three times, then the Engine Computer will prevent the system from working again until you wait half a minute or so.