Our 2011 Fiesta wouldn’t start, key in the ignition and all the interior lights would come up on dash and interior. Friend of mine said, “sounds like a relay”, came over and he swapped the low beam relay to the starter relay (said they where the same), car started just fine.
We put the bad relay in the glovebox, and planned to run to the auto store today. Except today it won’t start in the exact same way it wouldn’t start yesterday.
Do i have 2 bad relay’s in 2 days? Or as i suspect is this is a sign of a bigger issue?
Troubleshooting now, yes. You don’t know if the starter relay is bad. More often, the contacts in the starter solenoid are worn/pitted/oxidized (but this seems unusual for a car so new.) If so, they can be replaced, or cleaned up, so the plunger makes firm contact with two contacts.
But first: are you sure the battery and its connections are OK?
I suspect the relay diagnosis is incorrect and the fact that the engine started was purely coincidental.
Relays for low current applications seldom fail. Next time it won’t start I would suggest shifting into neutral and trying to start it.
Maybe the range selector switch is acting up and that’s a far more likely possibility than a relay.
I’m also assuming the complaint means there is no sound at all when the key is turned to the START position.
What you have most likely isn’t due to bad relays, it’s a misdiagnosis of the problem. It seems your vehicle uses some sort of starter relay, but there are other things involved in order to get the starter working. There is a starter solenoid and safety switch most likely involved also. The safety switch is the most common suspect for this kind of problem. If you have an automatic transmission try starting the engine in the ‘neutral’ position or move the shifter around in the park position while trying to start the engine to see if the safety switch contacts are just out of adjustment.
From what I can see, the relay is a 5 pin device, and called the “starter inhibit relay”. There are a bevy of other 5 pin relays plugged into the same relay panel, so maybe it is possible to swap them around. Hard to say. If the relays being swapped are the exact same part number then it is probably ok.
It looks like that relay’s purpose is to prevent the engine from starting in situations where it shouldn’t, like if the automatic transmission is in gear, or if a manual, the clutch pedal hasn’t first been depressed. It’s a safety device in other words. The transmission control module (tcm) is what grounds the relay coil, to activate it. The posts above are correct, the more likely cause of this fails to crank problem is either something wrong with the signal from the tcm, or a problem with the starter motor itself.
My guess, swapping the starter-inhibit relay had no effect at all, just a coincidence that the engine started afterward. More likely either the tcm isn’t recognizing that the transmission is already in P or N (or the clutch is depressed), or that there’s a problem with the starter motor.
If I had this problem: First, I’d remove, clean, then re-tighten the battery terminals. That alone might fix it. If not, next, I’d measure the voltages directly at the starter motor, terminal to case, both the battery and start terminal, during attempted cranking. If both are above 10.5 volts and it won’t crank, the starter motor needs to be replaced. If one or both are below 10.5 volts, find out why.
Edit: On some cars with automatics the brake pedal is involved in the starting process too. If the switch that detects the brake pedal is pushed isn’t working, this can result. Also if there’s an anti-theft system that’s not working.