The under-dash relay contacts must have been a little burned, they worked ok at first. but as they heated up they separated enough to increase the resistance a bit… The starter solenoid “start” signal requires about 20 amps, albeit briefly, used to move the starter gear out towards the flywheel and close the high current solenoid contacts. So the contacts of that under-dash relay need to maintain a resistance on the order of 1/20 ohms or less.
Hi Andrew, I am having same problem with my corolla 2003 ce. It started 4-5 months ago. Car ran fine in the morning (cool condition). After a stop it won’t crank immediately. It used to crank after few tries. This interval went longer with time. Last time I drive 5 days ago and I had to wait over 20 minutes after every stop to let the car cool down to start again. Since last 5 days it doesn’t start at all. I suspected the starter relay but couldn’t find it. Today I think I can guess it is mounted under the dash on the right side next to the radio. I can hear a click from there when I turn the key to crank. Before I take off the dash I just wanted to know if I am guessing the right location. Also if you have any picture of the relay it would help even more. I did put my hand through the glove compartment and could feel 3 relays there. Please help!!!