Test relays in circuit

[Hornnumb2]

I have a ipdm out of a nissan that the low beam headlight are not working. i believe it is a bad relay on the board. I had no luck finding the locally, they might need to come from china. is there a way to check them on the bench.

[redwire]

Re: Test relays in circuit

First check for bad solder/cracked joints on the module main PCB connector and the relay pins. The connector pins I see Nissan truck cracked solder joints on the PCB.
The relays rarely go bad, they get hot and melt if the contacts are bad.

If you pull the relay, you can test it on the bench using a car headlamp as a load.
You can swap the relay for another if you are OK with something else not working until parts come in.
Taiko YTB1-225L relay is available.

[Hornnumb2]

Re: Test relays in circuit

I just not sure which of the 8 is the low beam one to check, I guess i could unsolder all 8. are they available locally or under a different part number? I will check the joints under the microscope. Thanks Michael

[Hornnumb2]

Re: Test relays in circuit

All the pins look good, i can hear the high beam relay click but I hear nothing out of the low beam.

[redwire]

Re: Test relays in circuit

Check the daylight PWM dimmer module, if the car has one. I fixed a Nissan truck, the jumper links have cold solder joints in the small module for daylight low beams. It was a separate module.

Careful not to go on a goose chase. I check the fuses, low/high beams (bulbs), wiring and headlight switches.

You would have to follow the low beam wiring diagram back to the connector pin, to trace which relay it is. Or run the module open in the car and feel which one is clicking with a finger - but you say no clicking. You can always tap hard on the top to see if the relay gets unstuck.

Taiko YTB1-225 relay is out of china, the series root part number is TB1.
Panasonic has cross-reference to Taiko as TB high-power relays, like ACTBPDH4. It is a specialty automotive relay.

[Hornnumb2]

Re: Test relays in circuit

Yeah unfortunately I had to unsolder a 32 pin board that is stacked on top of the relays. so I dont think there is a way to hook it back up in its current state. I also used my scanner to activate the items in the ipdm and everything passes except the low beam.

[Per Hansson]

Re: Test relays in circuit

Just use a bench supply and feed the relay coils the required voltage at very low current.
You should hear them click and you can ohm them out with a meter at the same time.

[llonen]

Re: Test relays in circuit

If you have the relays out of cct then you can use a pulse / function generator, scope and current limited power-supply to test. I have repaired quite a few of these and or similar for clients, I order the relays from china they take about 10 days to get to me.

https://www.badcaps.net/forum/showthread.php?t=71359

This thread outlines the technique I use for testing relays, hope this helps.

[Curious.George]

Re: Test relays in circuit

Just use a bench supply and feed the relay coils the required voltage at very low current.
You should hear them click and you can ohm them out with a meter at the same time.

Without knowing how the coils are driven (high side switch vs low side, etc.), this could toast the driving stage. No joy, there.

Easier to see IF the coil has potential across it (if it doesn't, then the status of the relay is unimportant -- it's not being commanded ON!) and reason as to why that potential isn't translating into action of the armature.

[petehall347]

Re: Test relays in circuit

I just not sure which of the 8 is the low beam one to check, . Thanks Michael

you could try narrowing it down to see which ones do click by trying different things that use relays . or trace wiring colours back to relays . or swap 2 relays at a time . mark up where they are now though . high and low beam might even be same relay . pull that one out and count its pins .

[petehall347]

Re: Test relays in circuit

of course test both bulbs first . and fuses .

[R_J]

Re: Test relays in circuit

Have you tried looking for the wiring diagram for the vehicle

[redwire]

Re: Test relays in circuit

If you can ID the headlamp fuse, that is another way to trace it.
RLY1, RLY2, RLY10 you can see the coil connects to the high-side of one feed.

I would still look at the soldering joints, some look not great i.e RLY5 and others. Use a magnifier. You can wiggle the relay while looking at the PCB backside to see bad connections.

7G9H2116230 Renault Clio, Body Fuse Box Module is what search engines give back.

[jh20]

Re: Test relays in circuit

I would still look at the soldering joints, some look not great i.e RLY5 and others. Use a magnifier. You can wiggle the relay while looking at the PCB backside to see bad connections.

Or maybe easier to just simply re-solder them all anyway?

[redwire]

Re: Test relays in circuit

No - that doesn't find the problem. You'll never know if you actually fixed anything.
A good tech will go after and find the problem, then fix it. That way you don't get call-backs or have to redo a repair.
First I look for cracked, bad solder joints and then resolder the board's big through-hole parts if things look dodgy. Some automotive modules have poor soldering and joints crack with vibration and age on heavy parts.