Electrical getting hot, inertia switch help

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Mar 22, 2026 | 06:50 PM

VGVForrest

Thread Starter

Trailering

Joined: Jun 2025

Posts: 24

Likes: 1

Electrical getting hot, inertia switch help

Hey,
I posted in another forum and on Facebook but still need help here. I will post a link below to the other forum for anyone willing to read and catch up

Pretty much, the there's one particular wire going to the inertia switch that is getting hot. I reduced wire length and connections, and used solder connectors from amazon on this, and on my blower motor

I added a relay on my blower motor, ground-switched, in an effort to stop this one particular YELLOW ignition wire from heating up. It worked for a while, but now the relay is so sensitive that a bump will stop my fan from running.

What I've done for blower motor:
•Ground-switched relay
•New motor and thermal thing a few years ago.

Inertia switch:
•Swapped inertia switches with known good one
•Bypassed I. switch with paperclip
•New LP assembly and HP fuel pump + electrical cleaner on connections.
•Swapped ECM and FP relays but still the wires for I. switch get hot. Also, the 12V hot on the HP pump gets hot right at the pigtail

Here's the link and any help would be much appreciated

https://www.ford-trucks.com/forums/1801479-inertia-switch-help-2.html#post21791874

Last edited by VGVForrest; Mar 22, 2026 at 06:52 PM.

Mar 22, 2026 | 07:37 PM

90project5.0

Fleet Mechanic

Joined: Oct 2025

Posts: 1,778

Likes: 388

Look for and clean all the grounds in that system.
Theres either an excessive draw or bad ground.

Mar 22, 2026 | 11:16 PM

VGVForrest

Thread Starter

Trailering

Joined: Jun 2025

Posts: 24

Likes: 1

Quote:

Originally Posted by 90project5.0

Look for and clean all the grounds in that system.
Theres either an excessive draw or bad ground.

Will look for grounds for the YELLOW ignition wire and clean those . Fuel pumps share same ground at driver's side fender according to charm.li and I'm sure it's a good ground. Fuel pumps were replaced no only cause they were old and the HP gave out on me, but also in the hopes that one of them was drawing too much amperage and heating up my wires

I'll check my blower motor and blower motor relay grounds as well and verify all grounds with my power probe.

Thanks for the help. I'm learning a lot but there's still a lot to learn