Fuel pump relay integrated into fuse box?

Messages
2,751
Location
Kentucky
I purchased a 2015 Kia Sedona over the summer, and while doing a thorough inspection after getting the van home, I discovered someone had bypassed the fuel pump circuit and hot-wired a wire directly from the underhood fuse box (by splicing into another circuit using one of those add-a-fuse things) straight to the fuel pump. The fuse they tapped into was one that operates only when the ignition is turned on, so the fuel pump runs all the time whenever you set the car to the "ON" position with the push button, even when the engine is off.

If I remove the rigged up wire, the engine will not start and fuel pump does not run, so there's something wrong with the fuel pump circuit.

I took it to a KIA dealer and their technician told me the whole underhood fuse box needs replaced because they suspect the fuel pump relay is bad. He tells me the fuel pump relay is integrated into the fuse box.

Here is their description:

30263 FUEL PUMP POWER CIRCUIT BYPASSED FROM FUSE BLOCK TO PUMP
VERIFY RED WIRE [rigged up wire] GOES FROM FUSE BLOCK TO FUEL PUMP. INSPECT FUEL PUMP
FUSE AND SENSOR 3 FUSE. VERIFY FUSES ARE IN WORKING ORDER. REMOVE
CENTER CONSOLE TO INSPECT 12V FROM FUSE BLOCK TO FUEL PUMP AT CONNECTOR
EF11. NO POWER SUPPLIED FROM FUEL PUMP RELAY. RELAY INTEGRATED IN
ENGINE FUSE BLOCK. TEST CONTROL SIDE OF FUEL PUMP RELAY FROM ENGINE
ROOM FUSE BLOCK TO PCM CONNECTOR E100-A. CONTROL CIRCUIT TESTED GOOD.
DIAGNOSE FAULT TO BE IN ENGINE ROOM FUSE BLOCK CAUSING 12V TO NO BE
SUPPLIED TO FUEL PUMP.

In most cars, the fuse box is exactly that, just a plastic box with fuses and relays plugged into it. While I don't doubt the technician's diagnosis, I've never heard of relays being integrated into a fuse box assembly. Is this common and has anyone heard of this before? Seems like an awful dumb idea to me, relays don't last forever and there should be a means of replacing them other than swapping out the whole fuse box. Seems crazy to me.
 
Messages
3,476
Location
Chicagoland
FCA does the same thing... I remember having to have a recall done on my Durango because the relay in the TIPM would fail, their fix was a replaceable external relay.
 
Yes, common. The headlight relay is integrated with the fuse box in a 2011 Silverado. The new fuse box is a few hundred dollars. At first we bypassed it with a stand alone relay but eventually it developed gremlins so we replaced it.
 
Messages
5,845
Location
Suburban Washington DC
I've never heard of relays being integrated into a fuse box assembly. Is this common and has anyone heard of this before? Seems like an awful dumb idea to me, relays don't last forever and there should be a means of replacing them other than swapping out the whole fuse box. Seems crazy to me.

PCMs have relays inside and you never hear of just replacing a bad relay. No different for a fuse box. If it runs fine and ain't broke, why fix it?
 

92saturnsl2

Thread starter
Messages
2,751
Location
Kentucky
PCMs have relays inside and you never hear of just replacing a bad relay. No different for a fuse box. If it runs fine and ain't broke, why fix it?

Having the fuel pump hotwired in such a manner is a huge safety concern. The PCM has no means to shut off fuel flow in the event of pressure loss (large leak) or collision. Such safety mechanisms have been built into fuel pump circuits for the last 30+ years and for good reason.

Dealer quoted about $1,000 for fuse box replacement. I brought the issue up with the selling dealer and they're footing the bill. I've just never heard of relays integrated into the fuse box before. If the wiring is already there, how much trouble is it to put the relay in a replaceable socket? Seems silly to me.
 
Messages
1,030
Location
dayton oh
not uncommon to find fuse boxes with all sorts of junk integrated.
it gets worse.
i get ford superduty clusters in with failed "battery saver" junk in them.
relays die and your accessories stop working or go intermittent.
i will no doubt start seeing those kia fuseboxes in the future coming in for repair.
 
Messages
5,845
Location
Suburban Washington DC
Having the fuel pump hotwired in such a manner is a huge safety concern. The PCM has no means to shut off fuel flow in the event of pressure loss (large leak) or collision.

How would the PCM know to shut off fuel flow if the fuse box wasn't hotwired? I know Fords have an inertia switch to kill the pump but that is separate from the fuse box. Does Kia have that too?
 

92saturnsl2

Thread starter
Messages
2,751
Location
Kentucky
How would the PCM know to shut off fuel flow if the fuse box wasn't hotwired? I know Fords have an inertia switch to kill the pump but that is separate from the fuse box. Does Kia have that too?

All vehicles since the '70's are required to limit fuel loss in certain accident situations (FMV standard #301.) Different vehicles use different methods, Ford (and others) as you noted have used an inertia switch for decades. Many cars use input from the airbag control module.

I don't know the exact parameters the Kia is set up for, but as it stands, the fuel pump will keep running at all times unless you physically switch the ignition off. That would be difficult to do in a severe accident where you could potentially be incapacitated.

Outside of an accident, In the case of a large leak that would kill the engine, the fuel pump is supposed to shut off, nearly every car is set up this way. With the pump hotwired, it will continue to run unabated until the ignition is switched off.

The other problem is that there's those times I want to sit in the van with the ignition on and engine off and not have the fuel pump buzzing away needlessly. I don't think it's asking too much for the fuel system to be working correctly on a 28k mile vehicle I just bought! The dealer did the right thing, though it remains to be seen how they'll handle the repair. The KIA dealership isn't doing the work (selling dealer is), they brought it to KIA just to diagnose.
 
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Messages
5,176
Location
down in the park
Having the fuel pump hotwired in such a manner is a huge safety concern. The PCM has no means to shut off fuel flow in the event of pressure loss (large leak) or collision. Such safety mechanisms have been built into fuel pump circuits for the last 30+ years and for good reason.

Dealer quoted about $1,000 for fuse box replacement. I brought the issue up with the selling dealer and they're footing the bill. I've just never heard of relays integrated into the fuse box before. If the wiring is already there, how much trouble is it to put the relay in a replaceable socket? Seems silly to me.

Have not encountered any leak protection in fuel pump circuits, except common rail diesels. The Airbag control unit tells the "fuse box" to kill the fuel pump power in case of an accident, but before that they had an inertia switch or nothing at all.

However the fuel pump gets shut off if there's no rpm detected from the engine for a few seconds.
 

92saturnsl2

Thread starter
Messages
2,751
Location
Kentucky
Have not encountered any leak protection in fuel pump circuits, except common rail diesels. The Airbag control unit tells the "fuse box" to kill the fuel pump power in case of an accident, but before that they had an inertia switch or nothing at all.

However the fuel pump gets shut off if there's no rpm detected from the engine for a few seconds.

The fuel pump is turned off when engine RPM goes below a fixed amount. That effectively shuts off fuel flow in the event of a large leak where the loss of fuel pressure kills the engine. Most newer cars have the means to monitor fuel pressure in real time, though I’m not sure if a very low pressure input triggers the fuel pump to shut off.
 
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