How To Safely Probe A Relay Socket Without Damaging The Terminal

Sooner or later, when diagnosing an electrical issue on your Dodge Ram pickup (or just about any vehicle), you'll probably need to check for power or continuity at one of the terminals inside a relay socket —like the ASD or Transmission Relay— in the Power Distribution Center.

But here's the catch: you can't just shove a regular multimeter probe into the relay socket.

So in this tutorial, I'm gonna share some important testing tips that'll help you avoid damaging the Power Distribution Center (or any other fuse and relay box) —and still get the job done right.

APPLIES TO: This tutorial applies to the following vehicles:

• 1989-1993:
• Dodge Ram 150 Pickup 5.2L V8: 1989, 1990, 1991, 1992, 1993.
• Dodge Ram 250 Pickup 5.2L V8: 1989, 1990, 1991, 1992, 1993.
• Dodge Ram 150 Pickup 5.9L V8: 1989, 1990, 1991, 1992, 1993.
• Dodge Ram 250 Pickup 5.9L V8: 1989, 1990, 1991, 1992, 1993.
• Dodge Ram 350 Pickup 5.9L V8: 1989, 1990, 1991, 1992, 1993.
• 1994-2003:
• Dodge Ram 1500 Pickup 5.2L V8: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001.
• Dodge Ram 2500 Pickup 5.2L V8: 1994, 1995, 1996, 1997, 1998.
• Dodge Ram 1500 Pickup 5.9L V8: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003.
• Dodge Ram 2500 Pickup 5.9L V8: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002.
• Dodge Ram 3500 Pickup 5.9L V8: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003.

Use The Right Tool —Or A Safe Substitute

The terminals inside the relay socket are designed for precise fitment with the relay's male spade terminals.

Inserting a thick multimeter lead —or any oversized probe— that doesn't equal the thickness of the relay's male spade terminal will spread or permanently deform the female terminal.

If that happens, the relay will make poor or intermittent contact, leading to kinds of problems. In many cases, this means replacing the entire fuse/relay box, which is both an expensive and time-consuming headache.

The safest option is to use a dedicated terminal testing probe. The following links are examples of such tools (and you can buy'em there too):

• AUTOOL 68PCS Multimeter Test Leads Kit (at: amazon.com).
• LUTIFIX 68PCS Automotive Circuit Test Leads Kit (at: amazon.com).

But if you're in a pinch, here's a tried-and-true method:

• Use a Blue Male Insulated Spade Terminal Connector (16–14 AWG)—the kind commonly found in wiring kits at auto parts stores.
• The male spade is usually the perfect size for relay terminals —but test it first.
• If it feels too snug, lightly sand or file the spade down until it matches the thickness of the relay's original spade terminal. It should slide in with firm but gentle resistance.
• There's no need to crimp a wire into the connector. The multimeter test lead can press directly into the open barrel where a wire would normally go.
• If you need reach —like when testing from the relay box to the PCM—crimp in a short wire so you can clip onto it or run a longer jumper for your measurement.

Just Keep In Mind: this DIY method won't work in every situation. Some relay sockets are too tight, or the design doesn't allow enough room.

In those cases, you'll have to bite the bullet and invest in a proper set of automotive test probes. It's better than risking permanent damage to the fuse/relay box —which can turn into an expensive and a frustrating repair headache. So be careful, use common sense, and always test gently.

Why You Need To Be Careful Probing Relay Sockets

Relay terminals are fragile and precise. Even slightly expanding the female contact inside the socket can make it loose.

That means your relay might still "click" — but fail to pass current. The result? Hard-to-trace electrical gremlins like solenoid issues, random shifting, or even a no-start condition.

And I know I'm starting to sound like a broken record, but once a terminal loses tension, there's no easy fix but to replace the whole thing —and on some of these Dodge Ram pickups, that's a major job you want and need to avoid.

Final Tip: Always compare your test probe —or spade substitute— to the actual relay male spade terminal. It should be the same thickness.

If the probe you're using feels tight going in, stop and sand it down or use another thinner probe until it slides in with firm but easy resistance. Trust me, it's worth taking an extra minute to avoid wrecking the relay/fuse box.

More 5.2L, 5.9L V8 Dodge Ram Pickup Tutorials

I've written several more tutorials for the V8 Dodge Ram pickups that may be of interest to you that you can find in this index:

• 5.2L, 5.9L V8 Dodge Ram Pickup Index Of Articles.

Here's a sample of the tutorials you'll find in the index:

• How To Test The Fuel Pump (1992-2003 5.2L, 5.9L V8 Dodge Ram Pickup).
• How To Test The MAP Sensor -P0107, P0108 (1997-2003 5.2L, 5.9L V8 Dodge Ram Pickup).
• How To Test Engine Compression (1989-2003 5.2L, 5.9L V8 Dodge Ram Pickup).
• Troubleshooting A Blown Head Gasket (1989-2003 5.2L, 5.9L V8 Dodge Ram Pickup).