# Truck is burning out solenoid relays at an alarming rate. Please help troubleshoot. **URL:** \ **Category:** Factual Questions\ **Created:** [February 13, 2013, 5:55pm UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199 "2013-02-13T17:55:03Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![Renee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/renee/32/287_2.png) [@Renee](https://boards.straightdope.com/u/Renee)\ **Post date:** [February 17, 2013, 11:24pm UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199/21 "2013-02-17T23:24:44Z")
Yes, auto transmission. We were getting 0 voltage with the wire disconnected and the engine running. The only time we get voltage at the little wire is when it completely disconnected from the solenoid. ---
**Author:** ![Renee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/renee/32/287_2.png) [@Renee](https://boards.straightdope.com/u/Renee)\ **Post date:** [February 17, 2013, 11:26pm UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199/22 "2013-02-17T23:26:54Z")
We were also concerned about feedback from the starter, and my husband actually bought a new starter but didnt install it yet, wanted to make sure that could really be the problem before we put it in. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [February 18, 2013, 3:50am UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199/23 "2013-02-18T03:50:45Z")
I can’t see how a starter that functions well could cause this problem. [Here’s a case with some tempting similarities.](http://www.f150forum.com/f6/starter-solenoid-problem-83563/) It appears this one did have a problem somewhere in a wiring harness, but it wasn’t revealed where. It doesn’t look like I can be of further help from afar studying wiring diagrams. I think it’s going to take some hands-on checking of the truck to track down the short. ---
**Author:** ![Renee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/renee/32/287_2.png) [@Renee](https://boards.straightdope.com/u/Renee)\ **Post date:** [February 18, 2013, 6:16pm UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199/24 "2013-02-18T18:16:26Z")
> [@Gary\_T](#): > > I can’t see how a starter that functions well could cause this problem. > > [Here’s a case with some tempting similarities.](http://www.f150forum.com/f6/starter-solenoid-problem-83563/) It appears this one did have a problem somewhere in a wiring harness, but it wasn’t revealed where. > > It doesn’t look like I can be of further help from afar studying wiring diagrams. I think it’s going to take some hands-on checking of the truck to track down the short. Hmm. That guy had a short in the wire between the ignition and the neutral safety switch, which is interesting because we replaced the n/s switch last year. Perhaps that repair stressed the wire. Is it worth trying to see if the ground is bad? And if so, how do we do that? Thanks very much for everyone’s help. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [February 19, 2013, 5:48pm UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199/25 "2013-02-19T17:48:00Z")
> [@Renee](#): > > Hmm. That guy had a short in the wire between the ignition and the neutral safety switch, which is interesting because we replaced the n/s switch last year. Perhaps that repair stressed the wire. Is it worth trying to see if the ground is bad? And if so, how do we do that? We’re getting to the point where it’s not really feasible to instruct without being there. But there are three things worth trying: Disconnect the n/s switch wire connector and retest. If the stray voltage is gone the problem is in the switch. Inspect the wiring harness to the n/s switch for any sign of damage or deteriorating insulation. Check ALL the fuses and replace any that are blown. I’m afraid anything beyond those items will require some skilled troubleshooting. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [February 19, 2013, 6:54pm UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199/26 "2013-02-19T18:54:36Z")
I don’t think we are clear yet on which solenoid is burning up. Is it the starter relay, or the solenoid that sits directly on the starter? I am thinking something must be wired wrong somewhere, I have been a mechanic for over 40 years and don’t remember seeing and burnt solenoids where a direct short was not involved. I have seen plenty of toasted starter relays, mainly from loose or dirty harness plugs carrying too much resistance ---
**Author:** ![Renee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/renee/32/287_2.png) [@Renee](https://boards.straightdope.com/u/Renee)\ **Post date:** [February 19, 2013, 7:30pm UTC](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199/27 "2013-02-19T19:30:25Z")
It’s the relay on the firewall that we are having trouble with. We will take a look at the s/n switch and associated wiring. [Previous page](https://boards.straightdope.com/t/truck-is-burning-out-solenoid-relays-at-an-alarming-rate-please-help-troubleshoot/650199.md?page=1)