924s stereo wiring

[nagykurva]

Doing that with replacement used relay I get full voltage -12V.

[944er]

So, if you have 12V on pin R, 0V on pin 31, 12V on pin 30 (red) and low to no volts on pin 1 (red/blue) then I am afraid the relay has gone bad.

Next, you can look for cracked solder joints and/or try polishing the relay contacts if you want. You have to get the relay case off. What I have done is to clamp the case in a vice, grab the center pin with pliers and pull pretty hard, while pushing out the parts of the case that hold it onto the base with a screwdriver. It is a frustrating experience, but it can be done.

Once apart, look for cracked solder joints on the base. Then you can examine the contacts to see if they look burned/pitted/fried/ whatever. If so, use very fine sandpaper to burnish the contacts. If you are very lucky, your dad left you a relay contact file.

[blueline]

So, if you have 12V on pin R, 0V on pin 31, 12V on pin 30 (red) and low to no volts on pin 1 (red/blue) then I am afraid the relay has gone bad.

Next, you can look for cracked solder joints and/or try polishing the relay contacts if you want. You have to get the relay case off. What I have done is to clamp the case in a vice, grab the center pin with pliers and pull pretty hard, while pushing out the parts of the case that hold it onto the base with a screwdriver. It is a frustrating experience, but it can be done.

Once apart, look for cracked solder joints on the base. Then you can examine the contacts to see if they look burned/pitted/fried/ whatever. If so, use very fine sandpaper to burnish the contacts. If you are very lucky, your dad left you a relay contact file.

I'm forever amazed at tools mentioned that I've overlooked or ones I've never heard of - Carpokes is certainly one of the Kings of those revelations, at least regarding the automotive world.

I don't do much repair-wise, but in the years I've cleaned (or attempted to clean) contacts, it's been with fine grit emery paper or a fingernail emory board. I never considered that there were specific files for that. What's that about having and using the proper tool? I have a vague memory of that rule.

Just for fun, if nagykurva's Dad didn't leave him a pair of contact files, McMaster-Carr has plenty of varieties of them as I just found out. Not exactly cheap but they're probably the best.

https://www.mcmaster.com/products/elect ... act-files/

[nagykurva]

So then we suppose the used relay I bought has the same failure? Because it has the same voltage readings, and the sunroof also works with that one too.
Just curious , What should the red/blue ignition wire voltage be when working with the key in ignition?

[944er]

You said in post #19 that the red/blue wire is 10-19mV, it should be 12 V. This is the wire to the radio, there is no other red/blue wire to the relay. If there is 12V on 30, 12V on R, ground on 31, there should be 12V on pin 1.

radiorelay.png (845.68 KiB) Viewed 504 times

[nagykurva]

It’s funny you send that as I was going thru what notny41 sent to try to learn about the wiring diagrams…..

Original relay was taken apart…
I don’t see any obvious solder cracks….
The switch contact moves freely..
Any ones to empirically solder? 1..?

I’m not sure if doing something like irina did to test it out is worth it??

31 to ground.. 1 to 12v …. The 15 to 12v??

I will work on the contact file… none inherited…

[944er]

12V to R, gnd to 31, positive meter probe to 30, probe the traces on resistance through to 1 to find the break or contact problem.

[JamesM]

I would still clean all the contacts and do a reflow to rule out the possibility of microscopic solder joint cracks. I had a dme that had no visible cracks, but when I reflowed the dme, it started working again. I used alcohol to clean the film over the pcb and then used kester water soluble flux and kester water soluble cored solder. If you have any more questions about what I used feel free to ask. I would also consider changing the electrolytic capacitor and test the relay to make sure its not the mechanical part that is having an issue

[944er]

I think that cap has been changed already. I believe I have a photo of when I had mine open a few years ago, just need to get back from this trip to confirm. Resoldering or reflowing the base and the internal relay pins is a good idea, but I'm not sure I would reflow the rest if the sunroof auto lock feature works. There are components that are not available. All of the additional stuff in the relay is there to implement the auto-lock.

[944er]

Made it home, but cant find any photos so I cannot say definitively that the cap has been changed. I should also correct my statement in that there are a couple transistors and resistors on the large board used in the non-auto-lock mode. Pin 15 is connected directly to pin 2, and pin R is connected to pin 3 through a transistor, which is shut off by another transistor when pin 15 goes high. Sadly, I didn't reverse engineer past this, and I did not retain documents of what I found. Also, my memory may be bad.