[Bob Lincoln]

To make sure the battery isn't being pulled down, or the ignition switch is bad, remove the bypass and have someone measure the battery voltage while you hold the key in the start position. That tells whether there is a short or dying battery (battery voltage would plunge), or whether there is an open circuit (battery voltage remains unchanged around 12.4 to 12.6 volts).

 

[Bob Lincoln]

Or, could it mean that the relay is bad? Considering that the car will start when I bypass the relay, that would seem to make sense--except, when I test the relay with my multimeter, it checks out.

So, what does that mean? If the relay is good, and the car will start with a jumper between cavity #30 and #87, then it should start with the jumper removed and the relay back in place, right?

Except, the last time I tried to start it with the relay in place, the whole system died. But...if I have someone measuring the battery voltage while I try to start the car, then I have a dying battery or an open circuit. And that would be useful information.

Wait, though, the car started just fine with a jumper wire bypassing the relay! Surely that indicates that neither is the battery dying nor is there an open circuit. Right?

I think I should just put the relay back in place and try starting the car. What have I got to lose?

No, pins 30 and 87 are the load side of the relay. You jumped battery power across. If the relay tests good with the multimeter, but you have to remove it and bypass it to start, that tells me that the computer is not turning on the relay (at pins 86 and 85 of the relay), or, maybe less likely, the wiring to the coil side of the relay is damaged. So, no, plugging the relay back in won't necessarily allow it to start.