WallyP

Reading a post about an intermittent start problem started me thinking - not always a good thing...

I would like to have a more complete test rig for "53" relays.
This would be a relay base that plugs into the relay socket, and allows the relay being tested to plug into the relay base, piggyback fashion.
Coming out of the relay base would be a ribbon cable, with leads tapped onto each of the pins in the relay base, plus a couple of extra leads with alligator clips. One of these leads would be hooked to the main power point on the top of the Central Electric panel, and the other to the ground point above the panel.

The ribbon cable would connect to a PCB in a small box. The box, placed where you can easily see it from the driver's seat, would have labeled LEDs on the face. Nothing exotic in the box, just diodes to prevent back-feed.

These LEDs would show presence/absence of power on each of the relay terminals, and whether that power is being grounded thru the relay or the extra ground connection. The rig could also show presence/absence of ground on each of the relay terminals.

Think of how useful that would be! Pull the start relay, plug the tester into the socket, plug the start relay into the tester, and turn the ignition key to the start position. You instantly know whether the ignition switch is sending the start signal, or whether the neutral safety switch isn't grounded, etc.

There are quite a few "53" relays in the panel. This makes troubleshooting the fuel pump system (on later cars), start system, X-Relay, fog lights, LH, HVAC blower, defrost, and EZK a lot easier. You could install the rig and drive the car as long as it took to trap the gremlin, and would have an instant visual check on what is working/not working on the system being tested.

Someone want to make/sell these? I get a couple of free ones for the idea...

Leon Speed

I'd buy one

John Speake

Good idea Wally !

Would a stock relay socket act as the "piggy back" OK, or would it require a "Special" ?

NC928S4

I’d buy one...

Glen McCartney

I'm in as I am the one fighting an intermittent start issue

Jim M.

I'd buy one or more!

Tampa 928s

Kind of off topic but I have 2 break out boxes for the 85-86 years. You can attach test cables to a running car to test all the inputs and or sensors.

jpitman2

Wouldnt you need a way to observe/test the state of the conducting contacts - ie their ability to deliver full current demanded by the load, minimal voltage drop? When I first fitted electric fans to my car, and did a real test (at 100F, AC on, for nearly an hour), I just happened to touch the fan relay - HOT!!! Too hot to hold in the hand . A new replacement only got warm, so I reckon the old units contacts were burnt.
jp 83 Euro S AT 54k

WallyP

I suppose that a resistance measurement of the closed contacts might tell you a little about the current carrying capacity, but I doubt that it would be really useful. For example, sticking a sewing needle onto a copper plate would probably give close to zero Ohms, but the current carrying capacity would be close to nil. I suspect that you would have to do an actual load test to get any useful info. This test rig would not do that.

This rig would test the relay operation, but that is almost incidental. The higher value is in testing the circuit operations on a continual basis.

My first thought was that the actual relay in the circuit would be plugged into the new base (which is then plugged into the relay socket on the Central Electric Panel). So, what we need is a "53" (or "24") relay base, with a matching socket on top of it.

Eplebnista

http://www.lislecorp.com/divisions/p...s/?product=576

rbrtmchl

I like the idea of a more complete test rig. Last year when I searched and found the $200 solution, I searched more and found that Amazon sells a 5-Wire Relay Socket With 12-Inch Leads for $1.25. Using a 9 volt battery and a DVM, I was able to perform a few basic tests on a suspect relay.

WallyP

Again, that is to test relays.

The rig that I am proposing is more to test the circuits where the relay is installed.

dr bob

Things I look for:

-- Voltage at/across the coil terminals. Some 928 circuits depend on a switched ground to the coil, so it's better to look for potential at the actual coil terminals. A small light bulb across terminals 85 and 86 does this duty nicely.

-- Voltage Drop across the contacts with the coil engaged. A voltmeter across terminals 30 and 87 does this duty nicely.


FWIW, considering the cost vs. aggravation factor for these relays, by te time I get one pryed out for "testing", i'm ready to just plug a new one in at that time anyway. Not as much fun as a test fixture and the associated analysis, but could be a lot faster.

Also- I was just cruising the "pile of bits" that inevitably gathers at the back of the workbench. In that bin of bits there's an aftermarket foglight relay socket, with three feet of pigtails. A "spent" relay could easily be dissected to gain a male 'plug-in' for the CE panel end. I'd be tempted to add a handle to the old relay base to make removal easier when testing is done. A little service socket for a 194 bulb, along with said bulb, would take care of the first duty listed above. A pair of sacrificial test leads with hooded banana-plug ends could be included with connections to 30 and 87 , for easier connection to the meter for measuring voltage drop. Same connections extended to a heavy-duty toggle-switch would let you "test" circuits like the fuel pump when plugged in. An inline fuse in that switch loop would be handy too.

fraggle

I considered this a couple of times. I do have one stabdard relay with some leads soldered to it with alligator clips I use for testing. I figured some LED's for status, including signal, power, ground, and a couple of bypass switches - for system circuit troubleshooting - would be ideal.

Extra credit if you incorporate an ammeter for the and a voltage readout.

danglerb

Tooltopia has the relay buddy on sale right now for I think $50 and shipping.
http://www.tooltopia.com/electronic-...lties-190.aspx