How to build a Switch Relay Bridge for Fuel Line check
 

https://cimg7.ibsrv.net/gimg/rennlis...3c978beff9.jpg
As a newbie with my 88, I knew I had to change the Fuel Lines. I kept reading about Switch Jumpers which I saw them but Dr. Bob kept mentioning Switch Jumpers and I was intrigued, so I asked him about the Switch Jumpers what type of wire to use...thus making my own. (Thanks Dr. Bob regarding Lamp Wire information). I didn't want to use just a Jumper Wire. A jumper is needed because I was educated [on the forum] that the fuel pump doesn't come on like regular cards in Position 2 Ignition...It comes on when the car is cranking up. I wanted something with a switch, so after fuel lines installment, I could turn if ON and OFF whilst under the hood to check for fuel leaks. I hope someone finds it useful Cost to build about $12.00. I will always keep this in my Shark at all times. So, here you go...please bare with as this is the first write up on a How to:
Supplies:

• Off and On Switch (available at Home Depot)- with two .250 prongs
• Lamp Cord- 18gauge- 10Ft (Home Depot). Dr. Bob recommends 14 gauge.(read his reply suggestion below in thread)
• Male Disconnects (16-14), .250- Fully Insulated
• Female Disconnects (16--14), .250- Fully Insulated
• Relay Puller- Amazon-
  https://www.amazon.com/gp/product/B002NR2Z56/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
  https://www.amazon.com/gp/product/B002NR2Z56/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
• Fuse Holder (20A)-
  https://www.amazon.com/gp/product/B013JG8GIY/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
  https://www.amazon.com/gp/product/B013JG8GIY/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
• Plastic Pill bottle- Optional*
• Wire Strippers
• Brown Coffee Filters
• Flash Light
• Dexoit 100

SECTION TO CONNECT TO MALE/ FEMALE DISCONNECTS: Measure out at 6ft ( or longer if desired) of lamp wire. Go to one end. Take both ends of wire and pull them about 2-3" apart and strip the ends of the wire about .5 inch. Bend end of wire about 1/8" and twist it. Place the twisted end into the Female Disconnect and crimp it very hard...pull the end to make sure its secure. Place RED Heat shrink to identify the HOT/LOAD Side. Do the same thing for the other side for another Female Disconnect. These two connections will go to Rocker Switch.

The side that you have identified as HOT/LOAD, cut the wire into and place heat shrink on both sides of wires and solder the Fuse Holder into place. Then shrink the RED heat shrink at the soldered joints. I know this is redundancy to run a 20A Fuse' but since this is a 928, I felt it was a MUST. Fuse Holder should always go on LOAD or hot side

Go to the other end of the wire and do the same procedure as you did for the Female Disconnect, but this time use the Male Disconnect. Place RED Heat shrink to identify the HOT/LOAD Side.. These two connections will go to the CE Panel for the Fuel Pump Relay.

CONNECTING THE WIRES to ROCKER SWITCH: Insert the Female (RED-shrink wrap) on the LOAD side into the Male Connect on the Rocker Switch( look at your Rocker Switch to determine the LOAD side). Place the other Female Connector on the other side of your Rocker Switch.

CONNECTING WIRES TO FP RELAY: (NOTE...BEFORE DOING THIS, it is SUGGESTED to DISCONNECT your battery strap from the back. This is to protect any electrical situations when pulling the FP Relay since the Relay Puller tongs are metal. IMPORTANT REGARDING RELAY (30 & 87). 30 on the relay is always BATTERY, HOT!!!!!... ). The leads that go into the FP Relay on the CE Panel are the 2 (two) MALE connectors. Go to CE Panel and identify your FP Relay ( on my 88, it was XX-53,-but verify). Use the Fuse Relay puller and pull it out. Mind came out very easily with this tool. Once you have pulled the Relay out, go back to the back and reconnect your Battery Lead. Place the wire you have marked HOT (RED heat shrink) into 30 FIRST- (REMEMBER-30 IS HOT). Then place your other MALE connector into 87. Take your chord (gingerly) and go back to the engine bay and turn if ON. You should hear the FP come on!!! Use your hand to check or a brown coffee filter to check for Fuel Line leaks...hopefully everything checks out. When you are finished go back at your CE Panel and unplug 87 1st then 30. Before replacing relay, I used some Deoxit100

*ROCKER SWITCH HOLDER (OPTIONAL): I wanted the Rocker Switch to be inserted into something because 1) I could hold on something round (rather than the rocker switch) and 2) I didn't like the wires dangling from the Rocker Switch even though the FEMALE connects were insulated. So, get a Plastic Aspirin (whatever) bottle and using an exacto knife and cut out a section from the bottom of bottle that would accommodate the switch. Once you have cut out the right size, take the cap off the bottle. Take your bottle cap and drill about a 1/4 hole into the cap. Run the two female Disconnects thru the bottle cap and end of cut out section. Insert the wires on the Rocker Switch. Push in the Rocker Switch so clicks into place. Take your bottle cap and screw it on. Mark it OFF & ON :D

Nice write-up!

I suspect that the clear sleeves on your crimp connections are heat-shrink. Try a little heat and see if they grab the wire.

Well... they are insulated but don't know if they are heat shrink...I will check. I did add the black heat shrink opposite of the Load wire to make sure. Thanks Bob.

This is pretty timely as I just bought a SPST switch yesterday for this very purpose! The only significant difference between what I will be doing with my switch is using heavier gauge wire (probably 12 gauge or so). I used lamp cord before and noticed that the wires got pretty hot after awhile. Probably not an issue at all if you're just checking your fuel lines for a couple of minutes before startup, but in case I ever needed to use this for a longer time period for some reason I just thought I'd be extra safe. Great write up!

I hear yah Simon...Redundancy/ Overkill whatever you want to call it...is great vice.

Well done, frugal928!

Thanks Seth!

Simon brings up a good point. Prior to posting, the OP Frugal928 PM'd for some details on what he needed for the project. I need to go find the PM thread, but I'm almost positive (appropriate...) that I recommended 14ga lamp cord for the duty. Ten (total) feet of 14ga conductor will carry the max 20 amps of fuel pump current safely. The 18ga cord used by the OP is marginal for extended service. For those playing along at home, consider using 14ga lamp cord for this project. There's a reasonable chance that you will someday depend on this jumper to get you home from wherever your fuel pump relay no longer functions, so having adequate conductor size can be important.

Also, when you are out shopping for a switch, note the same DC current requirement on the switch. Hardware-store switches are typically rated for AC current flow. DC switches need a bigger gap between contacts when open so there's less tendency to arc-weld the contacts when you open the switch. Auto Parts stores are more likely to carry DC-rated switches, typically targeted towards auxiliary lights or other high-current accessories. This isn't critical bacause use of the switch will be intermittent at most, but if you are going shopping you have the chance to use the right part.

Bob...im pretty sure you told me to use 14 gauge... thus forgetting your recommendation. Thanks for the recommendations you stated. Btw the wires never got hot or warm since it was off and on within 10 sec or less. The purpose of this was testing fuel lines and to make changes according to what someone feels it's best for their set up ( a foundation How To). If I need to limp back home, I will use a jumper wire from 30 to 87 with the proper gauge. As far arching....i think a.fuse holder is good insurance

Good idea.

I built one of these a few years ago myself when troubleshooting a fuel pump relay problem and it now stays in the toolbox in the car along with 2 spare FP relays. I also labeled the wires with the terminal numbers where they should be plugged in so I wouldn't forget (#s are on the bottom of the removed relay).

Ill be using mine again as part of my engine R and R to check for leaks before firing anything up.

https://cimg7.ibsrv.net/gimg/rennlis...b47a36d962.jpg

Great idea labeling the contacts that go to FP relay. :thumbup:

Thank you, frugal928 for your detailed implementation instructions and links, Dr. Bob for providing the education, and Petza914 for the added refinements. I found myself needing to create a fuel relay jumper and this thread gave me the step-by-step I needed. ( A couple of other threads helped as well ).

I am adding the details of my implementation as another example with an added twister.

The first challenge I had was trying to find the right button. I took the advice of going with one from an auto store, because they tend to be DC rated and better suited for our application. In reality, however, the pickings were slim at the physical stores. Wanting to get this done sooner rather than later, I picked up several different switches to try. After several local auto stores, I never did find what I really wanted, which was a non-momentary pushbutton (SPST, off-on). I ended up using a water resistant (rubber booted) momentary button usually used as a starter button. I plan to order a more preferred button online and make another relay jumper in the future.

The second challenge was looking for a holder for the button. As frugal928 suggested, something more ergonomic was needed to hold the button. For me, preferably with a sci-fi theme. My future jumper - with more time to create it - will probably get closer to that. In looking around for an appropriate and ergonomic switch/button holder, I came up with the twister. I have several different old hot rod style center caps I have experimented with in the past and I just couldn't get away from the practicality of using one of them. Not only do they provide a sturdy base to hold the (momentary) pushbutton, but they can also provide storage for the wire. For now, my jumper needs to sit on top of a towel or fender cover/protector, but I hope to be able to add a removable (friction fit) rubber bottom so that it can stand on its own, anywhere you need it.

I'm very happy with this practical jumper and it worked like a charm as well!

https://cimg0.ibsrv.net/gimg/rennlis...15383345ea.jpg
^^^^^ American Racing plastic center cap (large).

https://cimg4.ibsrv.net/gimg/rennlis...bbbfe4ea7a.jpg
^^^^^ 5/8" hole on top as specified by the pushbutton, and 5/8" hole on side (edges sanded smooth with 220 grit sandpaper) for 14 gauge lamp wire, so the base can rest flat on the surface.

https://cimg2.ibsrv.net/gimg/rennlis...ac41cff262.jpg
^^^^^ Six feet of lamp wire can be stuffed in the base of this center cap (largest one I had). Unfortunately, it does not easily pull out/push in through the side hole. It is a less elegant and more manual process. (I did eye my vacuum cleaner and wonder about its auto-retract mechanism, but needed to just get this done.)

https://cimg0.ibsrv.net/gimg/rennlis...a67099d508.jpg
^^^^^ Final product - ergonomic!
(Note: I made the "87" tag angled to remind me it is the relay slot that does not line up with the others)

https://cimg7.ibsrv.net/gimg/rennlis...5390b1d1c5.jpg
^^^^^ In-situ, ready for action!

That is pretty awesome!!!
:rockon:

Great idea on using a container big enough to hold the wires when not in use.

Other options include drilling/fitting the switch right into the top of a gutted relay. Not as convenient for on/off duty under the hood, but it would make sure that the terminals are always correct into the CE relay socket. Option to extend the wiring to an external switch is there too.

I'll confess that, in 20+ years of maintaining my 30+ years old car, I've only used the jumper a few times. While checking for leaks after the intake fresh (found one...), and once while diagnosing a failing FP relay. It still lives in the tiny travelling tool bag, along with a cheap DMM (that's never been used on my own car...). Reminder: Change the battery in that travelling DMM every couple years. It's one of those $5 Harbor Freight specials, more than adequate for anything on the side of the road somewhere.

Here is the lazy way:

Fuel Pump Relay Bypass Kit | IPA Tools

https://cimg0.ibsrv.net/gimg/rennlis...55f0dc02b7.jpg