No, 30 is +12 volts from the underhood fuse block. Negative is the negative post on the battery, the body or frame, or the engine block. These items are all bonded together making them common to each other.

Don't worry too much about any electrical skills or lack thereof, we'll try and talk you through it.

 

Ok, here's the results of testing with a multimeter.

With the ignition switched "on" i.e., in the key in the normal running position, not the starting position, I get:
12V between negative terminal and 30
12V between 30 & 87
12V between 85 & 86
0V between 87 & negative terminal
0V between 87a & negative terminal

With the ignition switched "off", I get:
12V between 30 and negative terminal
0V between 30 & 87a
0V between 85 & 86
0V between 87a and negative terminal
0V between 87 and negative terminal

 

The relay isn't pulling in even though you have 12v across the coil of it (85 & 86).

With the key on, there should be 0v between 30 and 87 as well as 12v between 87 and negative.

Replace the ASD relay.

 

Another test to try is make a jumper wire to cross pin 30 with pin 87 on the relay slot and then try to start the engine. If the engine runs then try swapping the relay with another one near it, like the starter relay which you know is good. If your ASD relay works in the starter relay slot and still the van won't start then we should check for power to either pin 85 or 86, in my diagram one is called C-1 which should have 12 volts going to it when you look for power with the negative lead of your volt meter hooked to the battery negative post. The other is called the C-2 pin and is grounded by the PCM to turn on the relay.

 

I don't have a problem with trying a new relay, however as Mobile Auto Repair suggested, I already did try swapping around the relays in the fuse box (A/C relay and starter relay). When I switched the ASD relay with the starter relay, the starter still cranked, but no start - this would lead me to believe that the ASD relay is OK.

Here's another dumb question...should I have been probing across the terminals with the relay in place? I had the relay out when tested the voltage at the terminals in the fuse box.

Thanks both for the continued help.

 

No testing with the relay pulled is fine for you are telling us what the wiring harness is doing.

Did you try the jumper I suggested to see if you could make the van start that way?

 

I did not get a chance to try the jumper wire yet. Unfortunately, the van is currently stored about 70 miles away from where I live, so I don't have easy access to it.

 

Yes you should have. That would explain why pin 87 didn't have 12v to ground (negative). There was no relay in place to energize and subsequently no contacts to close in order to liven up pin 87 (the relay output).

 

See, I told you I'm bad with electric circuits. Ok, will re-do the testing when I get a chance. The relay is completely sealed, so I guess I'll just back it out 1/8th inch and stick the probes under it to contact the terminals.

 

It looks like I will have an opportunity to investigate my van's starting problem again this weekend.

I will try probing across the ASD relay terminals with the relay installed this time. Since, as I said before, the ASD relay has worked when swapped with the starter relay, I'm expecting that the voltage readings will be correct (I'll post the results again when I get them).

Assuming that the ASD relay is functioning properly, what would be my next step in tracking down this problem? Is there a way to determine if the PCM is getting power, outputting a signal, and functioning properly? What other areas should I be checking?

Just trying to look a couple steps forward since I only get to work on this van infrequently.

Thanks again.