Looking for an electric relay adapter fitting

[Furu]

Not certain if this is the best sub-forum area but will try.

I have a need to tap into a wire that is "ignition hot" off of a relay on a piece of equipment. Purpose is to run an aux fuel boost pump on a diesel engine. The OEM manufacturer told me that I should tap into a specific wire which goes into the relay output (50 amp, 12V). The problem is the wire that is outside the wire harness at the relay plug has less than 3/4 inch of available wire from the harness exit point to the plug.

I am not a fan of wire spice taps but there is not enough room to get one on it anyway at that location.

They (OEM) told me to just cut into the harness to get more wire available.

I want to avoid cutting into the harness if I can, so I thought I would turn to the collective knowledge of the group as I am certain someone out there has either the knowledge to tell me that what I am looking for exists or does not exist.

What I am hoping to find is if there is an adapter plug that can be plugged into the harness (female) and then into the relay (male) that has terminals or some such that I can connect to without the OEM's method of cutting the harness.

I have included a picture best I can of what I am taking about and the orientation of the plug/relay connection. The OEM sent me the pictures to show the location and wire. In the picture the harness appears to have more available wire than does my harness or it is an illusion.

 

[Coyote machine]

Does the new wire connection need to take place at the relay, or could it be connected at some other location further down the wire that might be more accessible?
Could you cut back the wire's insulation at a good location and then feed the connecting wire into the existing one to make a mechanical splice, followed by a solder connection and liquid electrical tape, etc. to seal the splice from moisture/ corrosion?

 

[Furu]

Yes but it is the same issue that I have to cut into the harness. Actually where the OEM wants/suggest that I cut into the harness is in another location that is "more" accessible. That is what I will do if I can't find the device/fitting I am asking about.

 

[Tractor Seabee]

What size wire are you tapping? 50A it could be #6 or maybe #8 if it is short. What size wire are you running to the fuel pump? If it is less than the 50A circuit wire does the pump wire have a fuse to protect the smaller wire? These answers may help us find what you need. There are tee splices for this application that crimp on the three ends. Crimping tools for larger wire are not normal for a DIY job, not sure about renting one. Happens I have one for wire from #8-0000. But that does not help you any. That is the easiest way and you only need about 2" of wire exposed to do it.

Ron

 

[Furu]

What size wire are you tapping? 50A it could be #6 or maybe #8 if it is short. What size wire are you running to the fuel pump? If it is less than the 50A circuit wire does the pump wire have a fuse to protect the smaller wire? These answers may help us find what you need. There are tee splices for this application that crimp on the three ends. Crimping tools for larger wire are not normal for a DIY job, not sure about renting one. Happens I have one for wire from #8-0000. But that does not help you any. That is the easiest way and you only need about 2" of wire exposed to do it.

Ron

I may have unintentionally mislead with the 50 amp comment. The relay, Tyco V23234-B1001-X004, has a 50 amp capability (Limiting continuous current according to the spec sheet I looked up) but the circuit is nowhere close to 50 amp. You can get an idea of the wire size in the picture even without a good reference. I do not know the wire sizes for certain as I can not get inside the harness but from the small amount visible I would guess 14 gauge. If I have to cut into the harness I will find out for certain what the wire gauge is.
I am using 14 gauge for the fuel pump and I am putting in a fuse even though the OEM did not address a fuse. I just decided that I was going to do it for my own comfort level.

As an aside I have been amazed at the wire sizes that are used in 12 volt systems from tractors to cars and trucks for circuits that are fused at pretty large values. I have never figured out how 12 V systems get away with such small wire sizes in vehicles and the like.

 

[Tractor Seabee]

For small wire I would use the crimp on tee connector. Auto Parts stores should have them as they are common. Use a Stake-On crimper not those cheap things that just flatten the metal out. NAPA will have or can get them. Naturally tape it up good after.

Ron

 

[Coyote machine]

Yes but it is the same issue that I have to cut into the harness. Actually where the OEM wants/suggest that I cut into the harness is in another location that is "more" accessible. That is what I will do if I can't find the device/fitting I am asking about.

Actually you don't have to cut into so much as strip back some insulation on the wire and weave in the wire you are adding, similar to what Tractor Seabee suggested with using a high quality T connector crimped connector. My way you solder and seal with liquid electrical tape; his way you splice/crimp and seal.
Auto/truck wiring is rated to amps passing through a circuit a certain distance with a fuse in the circuit. Relays allow isolation of higher voltage and amperage circuits to be energized by the relay and shorter runs of higher amp wires to cut wire costs and save space in bundled harnesses in crowded spaces. Having a fuse in your added circuit is a good idea too.

 

[David_Kb7uns]

I have spliced at relays two ways, either remove the pin from the socket and have wrapped wire around the pin where it grips the insulation and solder then cover with heat shrink or tape.

Other way is to do center tap a few inches down from relay connector.. You cut insulation and slide apart then split strands apart and thread new wire between strands and then wrap wire around itself and solder. Wrap with good 3M electrical tape and done.

You can use a quick tap but they cut wire strands and work loose.

David Kb7uns

 

[aczlan]

Yet another way would be to remove that connector from the relay socket, buy another relay socket, remove the same connector from it.
Then make up an adapter that has a male spade connector, a connection for you new pump and the connector that you removed from the new relay socket.
Then you plug the male spade connector into the plug from the old relay, connect the new pump and push the new relay connector into the spot on the old one.

Aaron Z

 

[The Fred]

It's a 5 minute fix with just one wire and a new relay to replace the one you now have. You can buy a relay with 5 spades and utilize the blank slot in the socket already installed on your engine there. The only downfall to this is that the wire you install in the blank slot will only be powered off the relay.

Cheap and easy. The picture I posted shows the wrong relay, the relay you need has 87 and 87B ganged together. This one toggles between 87 and 87A.

Here's the one you need:
http://www.texasindustrialelectric.com/relays_0332019203.asp



Fred