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Which wire for fuel-pump kill switch...?

XpedientJ

XpedientJ

NAXJA Forum User
Location
MA
'99 - Which wire is the power-run back to the fuel pump, for purposes of adding a kill-switch....?

20A-rated switch will be adequate??



Thanks.
 
I could be wrong but a switchable negative ground sounds like an idiotic electrical design to me... wouldn't it be better to switch the positive side? I don't know much about DC wiring though.
 
i thought i read somewhere that cuttin off the fuel pump on a newer xj throws a cel code.. I could be wrong though
 
would a regular 12v toggle switch work as well?
 
see i eventually just went and light tested the wires because after searchin on how to do it then actually doin it it became clear that different years the wires were different colours and routed differently...like most right ups i found said the wres would be in the wire loom along the driver kick panel...mine(89) had the wires runnin under the carpet along the tranny hump and bein different colors then they were spose to be i just got someone to work the ignition while i check the wires to see which was hot then mounted the switch by the seat belt bottom and i just uses a simple rocker switch from the source(curcuit city)
 
mud-dog27 said:
see i eventually just went and light tested the wires because after searchin on how to do it then actually doin it it became clear that different years the wires were different colours and routed differently...like most right ups i found said the wres would be in the wire loom along the driver kick panel...mine(89) had the wires runnin under the carpet along the tranny hump and bein different colors then they were spose to be i just got someone to work the ignition while i check the wires to see which was hot then mounted the switch by the seat belt bottom and i just uses a simple rocker switch from the source(curcuit city)
Click to expand...


hey i got the same wires as you. what one did you cut?(colour)
 
darjevon said:
I could be wrong but a switchable negative ground sounds like an idiotic electrical design to me... wouldn't it be better to switch the positive side? I don't know much about DC wiring though.
Click to expand...
Makes no difference. A lot of OEM uses ground as the interrupt instead of positive. I think it would be better to use the Fuel pump relay trigger wire then there is only milliamp draw on a switch. Maybe more reliable?
 
A ground interrupt will work fine. You can have all the power in the world going back, but unless you have a ground nothing is happening. The only reason I would use a power wire is because it is located right beside the driver's seat. I don't think the ground is.
 
I know we are talking about a newer xj but FWIW on the renix(87-90) all you have to do is run wires from a switch in the cab out to the ballast resistor wires for an easy to do fuel pump kill switch.
 
I know this is an old thread, and I know this topic has been discussed, but nothing I have really found answers my questions.


Like this thread initially asked, would it be alright if I put a 20 amp switch on the ground wire to cut the power to the fuel pump?

I found this thread, and people were saying to use a relay and a heavy duty switch, but it seemed to be because of the long lengths of wire being used.
http://naxja.org/forum/showthread.php?t=33495&highlight=fuel+pump+kill+ground


So if I cut the ground wire close to the kicker panel and used a 20 amp switch to interrupt the ground, will that work?
 
Starboard M said:
I know this is an old thread, and I know this topic has been discussed, but nothing I have really found answers my questions.


Like this thread initially asked, would it be alright if I put a 20 amp switch on the ground wire to cut the power to the fuel pump?

I found this thread, and people were saying to use a relay and a heavy duty switch, but it seemed to be because of the long lengths of wire being used.
http://naxja.org/forum/showthread.php?t=33495&highlight=fuel+pump+kill+ground


So if I cut the ground wire close to the kicker panel and used a 20 amp switch to interrupt the ground, will that work?
Click to expand...

On my 90 the power feed is a 14 gauge wire--not what I would call "heavy" gauge. I found a nice rocker switch at RS, it happened to be a 30 amp 12 VDC but I bought it for its shape and mounting. Part number 275-0018, its been working fine for two years running.
 
i just put a RS 20A in-line with the power to the pump. the LED lights up correctly and has been working fine for almost a year. in mine (97) there were two wires the same exact color and size running to the pump. ofcourse the second one i cut was the correct one
 
snail said:
i just put a RS 20A in-line with the power to the pump. the LED lights up correctly and has been working fine for almost a year. in mine (97) there were two wires the same exact color and size running to the pump. ofcourse the second one i cut was the correct one
Click to expand...

Yeah, that is the way it seems to go! :cheers:

Some days you are the dog, some days you are the hydrant.
 
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