# 2012 Ford F-150- fast flashing turn signal **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** ford, f150\ **Created:** [July 1, 2021, 11:04pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799 "2021-07-01T23:04:55Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\ **Post date:** [July 2, 2021, 12:35pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/22 "2021-07-02T12:35:41Z")
Does this truck have a plug for trailer lights? Make sure the wiring to it isn’t shorted out, a lot of times light problems can be traced to a bare wire in the trailer harness touching the frame or hitch. ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 2, 2021, 1:14pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/23 "2021-07-02T13:14:10Z")
It does have a trailer light plug and it has been checked. Thank you. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [July 2, 2021, 5:56pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/24 "2021-07-02T17:56:17Z")
> [@Nevada\_545](#): > > Be sure to use the correct bulbs, some systems will give the bulb out alert (fast flash) if the bulb resistance is incorrect. +1 My '74 Volvo had a bulb burn-out warning light on the instrument panel. I found out by trial and error that the system was so sensitive that both of the bulbs on a particular circuit had to be the same brand, as well as the same type. It drove me to distraction until I figured this out. Apparently, even the extremely minor difference in resistance from two _supposedly_ identical bulbs of different brands was problematic for that Volvo’s electronics. ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 3, 2021, 2:27pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/25 "2021-07-03T14:27:10Z")
My hyperflashing turn signal is still flashing very fast. New front and rear bulbs made no difference at all. I ever disconnected the battery for 15 minutes thinking it might ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 3, 2021, 2:29pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/26 "2021-07-03T14:29:18Z")
Hoping I was going to reset the electronics with the battery disconnected but no such luck. ---
**Author:** ![weekend-warrior](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/weekend-warrior/32/26122_2.png) [@weekend-warrior](https://community.cartalk.com/u/weekend-warrior)\ **Post date:** [July 3, 2021, 4:00pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/27 "2021-07-03T16:00:21Z")
are you using standard bulbs or led bulbs? ---
**Author:** ![weekend-warrior](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/weekend-warrior/32/26122_2.png) [@weekend-warrior](https://community.cartalk.com/u/weekend-warrior)\ **Post date:** [July 3, 2021, 4:15pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/28 "2021-07-03T16:15:26Z")
if your truck calls for standard bulbs you have to use standard bulbs. if Led , you have to use led bulbs. you cant mix them or you will get hyper flashing. ---
**Author:** ![mathewdexter136\_163193](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mathewdexter136_163193/32/19574_2.png) [@mathewdexter136\_163193](https://community.cartalk.com/u/mathewdexter136_163193)\ **Post date:** [July 3, 2021, 5:44pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/29 "2021-07-03T17:44:34Z")
I had the same problem on the left side. To make things worse it was intermittent. Someone posted earlier to replace both bulbs. I did that, problem solved! ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [July 3, 2021, 6:12pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/30 "2021-07-03T18:12:03Z")
It sounds like the micro-processor in the body control module for the right side turn signal has failed ![image](https://global.discourse-cdn.com/cartalk/original/3X/7/e/7e926463336ac7840f3f7184aad53988cf6bd48d.jpeg) Tester ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 3, 2021, 6:17pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/31 "2021-07-03T18:17:30Z")
Using standard bulbs all around. ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 3, 2021, 6:24pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/32 "2021-07-03T18:24:22Z")
@Tester, that makes sense to me but I’m thinking it is something I might have to find a service technician for. I have one in mind but it will have to wait until next week. I don’t even know where the BCM is located. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [July 4, 2021, 12:02am UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/33 "2021-07-04T00:02:17Z")
Next step is to measure the resistance of the bulb filaments with the bulbs installed in their sockets. This measurement should be done by probing at the body control module, using the body control module ground as well. This may require some circuit probing skills that most folks don’t have. If so, ask a shop having a good electrical-diagnostic staff for assistance. ---
**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\ **Post date:** [July 4, 2021, 12:21am UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/34 "2021-07-04T00:21:32Z")
Try removing relay 37 & 38 in the fuse box under the hood, they are for the trailer wiring turn signals. Just to eliminate the trailer wiring as the problem. ![Capture](https://global.discourse-cdn.com/cartalk/original/3X/6/b/6babdfff4b9eb41f703a24f86e0178d3e81fa8f9.jpeg) ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 4, 2021, 1:00am UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/35 "2021-07-04T01:00:11Z")
Removing those made no difference but thanks for the suggestion. ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 12, 2021, 8:46pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/37 "2021-07-12T20:46:56Z")
Got the problem fixed today. I was told the technician assigned to the job found voltage in a ground wire. The shop manager could not explain why it didn’t blow a fuse but was causing feedback through the turn signal circuit. He said it’s something they usually find in a vehicle that has been in a accident. Said the ground wire was fused to a hot wire. Anyway, just glad to get past this issue. Thanks for all your input. I appreciate it. Just to bad I’m such an electrical idiot. ---
**Author:** ![weekend-warrior](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/weekend-warrior/32/26122_2.png) [@weekend-warrior](https://community.cartalk.com/u/weekend-warrior)\ **Post date:** [July 12, 2021, 8:48pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/38 "2021-07-12T20:48:46Z")
glad its solved. and thanks for posting back with the solution. it may help others. and us. even the best mechanics are always learning. ---
**Author:** ![Renegade](https://avatars.discourse-cdn.com/v4/letter/r/b4bc9f/32.png) [@Renegade](https://community.cartalk.com/u/Renegade)\ **Post date:** [July 12, 2021, 10:02pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/39 "2021-07-12T22:02:13Z")
> [@alke46](#): > > Thanks for all your input. I appreciate it. Just to bad I’m such an electrical idiot. I would not say you are a idiot at least you stayed after until you got it fixed and thank you for letting us know the outcome. ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 12, 2021, 10:35pm UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/40 "2021-07-12T22:35:32Z")
Thanks for the inspired response but I can not take credit for the fix. I only took it to someone who could fix it. ---
**Author:** ![Renegade](https://avatars.discourse-cdn.com/v4/letter/r/b4bc9f/32.png) [@Renegade](https://community.cartalk.com/u/Renegade)\ **Post date:** [July 13, 2021, 12:01am UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/41 "2021-07-13T00:01:38Z")
> [@alke46](#): > > Thanks for the inspired response but I can not take credit for the fix. I only took it to someone who could fix it. You can take credit for knowing when it got to beyond what you could do and asking for help here and from someone who did know. ---
**Author:** ![alke46](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@alke46](https://community.cartalk.com/u/alke46)\ **Post date:** [July 13, 2021, 1:15am UTC](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799/42 "2021-07-13T01:15:52Z")
Good point. [Previous page](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799.md?page=1) [Next page](https://community.cartalk.com/t/2012-ford-f-150-fast-flashing-turn-signal/177799.md?page=3)