F150 supercrew
Junior Member
Joined: Oct 2015
Posts: 10
Likes: 0
Theft light blinking and no start
Had this problem years ago. One question: Did you get rain recently?
Very common problem in 97-2003 F150s. Windshield leak that allows water to get into fuse panel or the generic engine module (GEM) which when they’re wet will result in the symptoms you’re experiencing. It happened to me about 3 times before I realized the connection with the rain. Replaced the windshield and never had the problem again.
However the GEM card if it gets wet enough will exhibit other longer lasting issues; for me, it messed up the shift on the fly capability. I can shift into 4h in Park and start car and it will engage perfectly fine but will be stuck in 4hi until I restart in Park and 2wd. Likewise if in neutral and 4Lo it will work fine, but am in 4Lo until I restart in Park and either 2wd or 4hi. There are about 400 of those GEMs on backorder with Ford but they don’t make it nor do they have a supplier for it. So it’s work with the one you have or take your chances with a junkyard unit.
I cleaned my GEM with electrical contacts cleaner and the shift on the fly worked perfectly for about a week then back to the above not working.
Sorry for the long response but if you recently had rain I’d point to the windshield issue.
Very common problem in 97-2003 F150s. Windshield leak that allows water to get into fuse panel or the generic engine module (GEM) which when they’re wet will result in the symptoms you’re experiencing. It happened to me about 3 times before I realized the connection with the rain. Replaced the windshield and never had the problem again.
However the GEM card if it gets wet enough will exhibit other longer lasting issues; for me, it messed up the shift on the fly capability. I can shift into 4h in Park and start car and it will engage perfectly fine but will be stuck in 4hi until I restart in Park and 2wd. Likewise if in neutral and 4Lo it will work fine, but am in 4Lo until I restart in Park and either 2wd or 4hi. There are about 400 of those GEMs on backorder with Ford but they don’t make it nor do they have a supplier for it. So it’s work with the one you have or take your chances with a junkyard unit.
I cleaned my GEM with electrical contacts cleaner and the shift on the fly worked perfectly for about a week then back to the above not working.
Sorry for the long response but if you recently had rain I’d point to the windshield issue.
Junior Member
Joined: Oct 2015
Posts: 10
Likes: 0
Another thing
If you did have rain recently, and you get desperate to need it for work you can get a hair dryer and blow air up under the dash in the fuse panel area (under the steering wheel) and it will slowly dry it out enough to be able to start it. I had to do that very thing The last time it did it to me.
Senior Member
Joined: Nov 2017
Posts: 6,637
Likes: 1,293
From: Washington
That's good info Macon. Don't forget a car wash as a water source.
But, how did you diagnose the problem? How does a person know it's the GEM getting wet? What did you do in the 2 times before you realized it was water from the windshield?
But, how did you diagnose the problem? How does a person know it's the GEM getting wet? What did you do in the 2 times before you realized it was water from the windshield?
Senior Member
Joined: Nov 2017
Posts: 6,637
Likes: 1,293
From: Washington
That's good info Macon. Don't forget a car wash as a water source.
But, how did you diagnose the problem? How does a person know it's the GEM getting wet? What did you do in the 2 times before you realized it was water from the windshield?
Edit - wrote this while you were writing "another thing". Still, how do you know?
But, how did you diagnose the problem? How does a person know it's the GEM getting wet? What did you do in the 2 times before you realized it was water from the windshield?
Edit - wrote this while you were writing "another thing". Still, how do you know?
Junior Member
Joined: Mar 2017
Posts: 29
Likes: 3
No Start
I owned a 2002 Lariat SuperCrew for almost 14yrs. I had your problem Twice.
The dealer had to fix it, my keys (for whatever reason) weren't being read by the ignition.
Oh and before I sold it (over a year ago) I had to replace the fuel pump (about 140K miles on it at the time). The problem sounds very similar to the key not being read.
The dealer had to fix it, my keys (for whatever reason) weren't being read by the ignition.
Oh and before I sold it (over a year ago) I had to replace the fuel pump (about 140K miles on it at the time). The problem sounds very similar to the key not being read.
F150 raidermann1979
Joined: Mar 2018
Posts: 18
Likes: 3
From: OH
I owned a 2002 Lariat SuperCrew for almost 14yrs. I had your problem Twice.
The dealer had to fix it, my keys (for whatever reason) weren't being read by the ignition.
Oh and before I sold it (over a year ago) I had to replace the fuel pump (about 140K miles on it at the time). The problem sounds very similar to the key not being read.
The dealer had to fix it, my keys (for whatever reason) weren't being read by the ignition.
Oh and before I sold it (over a year ago) I had to replace the fuel pump (about 140K miles on it at the time). The problem sounds very similar to the key not being read.