When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi all,
I've another problem with the F250 of my daughter. This morning, no start, but at 3rd try it starts ! I shut the engine, no start again and now it never starts. I see that radio and clock come off when i was in start position but not the interior lights. Battery is new and no voltage drop when i try to start. I put a test light on the coil terminal relay (R/LB small wire), no light when i try to start; if i remove this wire, put the ign. switch in "run" and send 12V on the relay terminal the truck starts !
So the problem isn't in the starter relay but surely in the ignition switch. Where it is ?
So the problem isn't in the starter relay but surely in the ignition switch. Where it is ?
Before diving any deeper, can you please clarify what happens when you said the engine would not start? Did the starter still engage as normal to spin the crankshaft? If the starter never engaged, that's a big difference in how to troubleshoot.
If you're positive the ignition switch is at fault, details are at this link. The switch itself is located on top of the steering column, under the dash. Click on the second tab in the middle of the page. Replacement is not difficult at all.
Yes the starter doesn't engage and the relay doesn't "click"
Let's see if the starter relay (the big one on the fender, just aft of the battery) is receiving the proper command to close and route power to the starter itself.
On the side of this relay, you should see one or two small terminals. Look for the one labeled S. If there's a second terminal, it will be labeled I, but you can leave that one connected.
Turn the key to off and remove it. Put the transmission in park or neutral, as the engine will turn for the next step. Use a jumper lead between the battery's (+) terminal and the small S terminal on the starter relay. This mimics the normal start command via the ignition switch. The starter relay should close (big clunk noise) and send power to the starter. Even though the starter will spin, the engine won't start because there's no spark due to the ignition key removed. For the moment, I'm only concerned with why the starter won't run.
If the starter now runs okay, there's a problem in the command circuit via the ignition switch. That could be a bad ignition switch, blown fuse, neutral safety switch, or broken wire.
If you get the big clunking noise from the relay, but the starter still doesn't run, we can investigate further. That could be a bad relay, a very weak battery, or a bad cable.
No clunk at all from the relay (and no starter movement) is likely to be a bad relay, a very weak battery, or a poor ground at the relay base.
. Use a jumper lead between the battery's (+) terminal and the small S terminal on the starter relay. This mimics the normal start command via the ignition switch. The starter relay should close (big clunk noise) and send power to the starter. Even though the starter will spin, the engine won't start because there's no spark due to the ignition key removed. For the moment, I'm only concerned with why the starter won't run.
If the starter now runs okay, there's a problem in the command circuit via the ignition switch. That could be a bad ignition switch, blown fuse, neutral safety switch, or broken wire..
I've done that, the relay and starter engage (and the engine starts if key in "run" position) if i use a jumper lead.
As i said ther's no 12v on the S terminal wire when key is in "start".
Could i bypass the Neutral switch ? Where is its connector ?
You can try turning the key to start and move the shifter to see if the starter will crank the motor over.
If so then yes for sure the NSS could use adjusting.
Now even if it does not turn over it could still be the NSS.
I want to say it is on the side of the trany where the shift linkage goes into it.
It should also be the back up light switch I just don't know what color wires are for the starter.
Dave ----
As i said ther's no 12v on the S terminal wire when key is in "start".
Oops, I was less correct than usual and missed that.
The NSS or ignition switch could be the culprit. Play with the gear shift as Dave suggested. The engine should start in either P or N, so try both. Foot on the brake, wiggle the lever while turning the key in case the NSS is out of adjustment.
If no help, you'll have to do some basic troubleshooting to determine why power isn't reaching the S terminal. Either switch could be bad. Could be a broken wire or blown fuse. Hard to tell from here.
You didn't mention what year or engine, but some wiring diagrams are here:
If no help, you'll have to do some basic troubleshooting to determine why power isn't reaching the S terminal. Either switch could be bad. Could be a broken wire or blown fuse. Hard to tell from here.
You didn't mention what year or engine, but some wiring diagrams are here:
I've tried to wrigle the shift lever without result ... Ther's a fuse on these wiring ? This afternoon i'll first try bypasing the NSS, seems that the NSS has a 4 blades connector when i look at replacement and i know the colors ( R/LB)
Year and engine are in my signature : 1986 truck 460 engine
Problem solved !!! I lowered the steering column and tested the switch: seems that sometimes it's ok and sometimes not. Suddenly i noticed that if i help the rod to go further ther's a continuity between 37Y(batt) and 32 R/LB (the starter relay command). I'm an idiot, i didn't rotated far enough the key lock cylinder in "start" position, ther's a double detent, and i didn't turn after the first detent, the second is harder and on my '70 Ford which has the same lock cylinder i didn't noticed this dual detent. so I spent 4 hours for nothing ... But now i know where is the NSS, the ignition switch, and how to access .
In fact itsn't my truck but the truck of my daughter ... When something goes wrong she calls me and says "hey Dad' you must repair this problem..." I took the truck because the two door panel windows switch had fallen below the panel and not for the start problem. As i didn't drive it very often I am not used to the small details of the truck.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
