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I've fixed relays in the past but never on a rebuild and there's some weirdness to me on this one.... Lots of wires bypassing the board and the relay is GLUED down through the pin holes for the old relay. YUCK! What would you do?
Umm whats the problem with the HVAC unit you have now? before you go about touching the added on relay?
Maybe the relay is still working as it should?
Yeah. Good question. I will be doing a full troubleshooting on this new to me vehicle. Suffice it to say, if I address any other suspect wiring and there are no blown fuses, yet there is no power to freeze switch that the relay is blown, right?
put another way if the relay has been replaced then the chances are good its still in working order and other things should be looked at first.
Prime in the HVAC head are the finger wipers I have found many times that dirt will adhere to the grid plate and then get stuck under one of the finger wipers, this will stop a certain part of the system from working.
remove the finger plate clean the grid,
bend the fingers a lil bit so they make positive contact and put some D100 on the grid and work the finger plate.
Also check the cb for burned traces
I don't see any burned traces and wasn't sure if the coating (sticky) on the grid where the fingers wipe was supposed to be there. Looks grungy to me. Picture below...
I do have some troubleshooting to do after I repair some wiring issues at the fan. Previously, the compressor was unhooked and a fuse was blown. I hooked up the compressor, replaced fuse and charged up system. Next time I went to use it (within a couple of hours), I turned on the AC and immediately lost blower, compressor and HVAC control response. No blown fuses.
While I have the center console out, I just want to make sure the HVAC unit is in it's best shape. I'll be adding a fuse at the freeze switch, too. and following Wally Plumley's AC troubleshooting.
Umm whats the problem with the HVAC unit you have now? before you go about touching the added on relay?
Maybe the relay is still working as it should?
It's been discussed by people far better versed in electronics than me, that relay is undersized and prone to fail. I'll be adding an external one per Alan's instructions the next time I pull my console apart.
IMO when it's working is the best time to do this job. That way you know it's still working after the job is complete.
Eric brother , that Relay that was posted in picture 1 is not the factory undersized relay,
Since the OP is posting this I suggested that the HVAC system issue may be caused by another part of the system,
since the original relay has already been replaced.
I do agree with your last statement. fix it while its not broken.
I have a secondary control head coming to me from EBay, as well (I couldn't pass up $85 for the unit). Both the one I have and the ebay one will get the relay treatment as I have another S4, which to my knowledge, hasn't had the relay replaced.
I'd love to see a pictorial on taking apart the things Stan mentions, cleaning and putting back together. I'm not sure I've seen anything other than just the relay procedure (from Dwayne).
once you get the covers off the HVAC unit its self evident on what the grid panel looks like,
and how to remove the E clip to take it apart
Fair enough but did the wipe area appear dirty to you in the picture I showed? It is sticky which I assume is bad and could be cleaned up with Deoxit 5?
when you take the finger pad off,
then take a picture.
Notice how some of the fingers may not be applying the same amount of force to the grid,
bend them slightly so they are even also look for dirt particles on the fingers
02-19-2019, 06:11 PM
How to fix this HVAC Relay?
