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Old 04-17-2022, 03:29 PM
brandon121 brandon121 is offline
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Join Date: Mar 2014
Posts: 3
Post My 2003 ford ranger fx4 4.0L SOHC

hey everyone,

I own a 2003 Ford ranger 4.0 fx4 level 2 SOHC, it has some wiring issues in the engine bay.

a little information about the truck,

its my first vehicle i purchased off a drunken mechanic. he had it slightly taken a part and pieced it back together to sell to me. blow the motor due to loose hoses and lack of hose clamps he neglected to put on. Then he changed the motor for me and put in a 04 engine.

he then told me that the old 03 engine, and the newer 04 engine have slightly different wiring harnesses and basically scabbed the 2 harnesses together enough to make the truck run for me. which it did and for a decent amount of time. only problem was it was lacking the use of A/C, cruise control, temperature gauge on the dash, sadly 4x4.

i drove it for many years like that and it sat for a few years aswell. until last year when i drove a lengthy trip from vancouver island to the rocky mountains and back, on my way home 10k from my house my thermostat failed. unknowingly due to the lack of coolant temperature gauge not working, i was left to tow it home and deal with it myself.

i took it upon myself to fix the thermostat. i changed the upper and lower housing, thermostat (inside) and also both temperature sensor AND sender. cause it has both a sensor and a sender.

i took it apart and pieced it back together through the help of some youtube videos.

it has since started and run/idled very poorly. havent been driving it around.
i threw my code reader on it to try and monitor the coolant temp, which it keeps reading +300(degrees) Fahrenheit. which is basically boiling my coolant. i think i let the truck run and idle for maybe like an hour with no problems of overheating/steaming or anything, but like i mentioned it was a pretty rough idle, and i believe it stalled on me a couple times while trying to drive it around the block.

so i bought a old/used wiring harness made for the same truck 04 motor with 4x4 and i was wondering if anyone knows if both the 2003 and 2004 4.0l 4x4 engines will have the same wiring harnesses or would be able to easily modify the new/old/used harness i bought off ebay.

i understand its easy to just take it all apart and find out based off plug and play, but im looking for EXPERT advice and knowledge on the subject. any will help, i can answer more questions to help give more detail.

thanks for your time!

happy trails
2003 Ford Ranger FX4 Level 2
6 cyl. 4.0L XLT supercab

Last edited by brandon121; 04-19-2022 at 10:21 AM.
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Old 04-17-2022, 03:37 PM
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Old 04-17-2022, 09:43 PM
DrWh042 DrWh042 is offline
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Default Re: engine bay wiring harness

welcome to the forums!
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4.0 engine, temp gauge, temperatures, thermostat

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