Caddy Maxi 1.6 heater blower not working

[Doc]

Relays are good. I just double checked them all.

You sure??

[Odo13tz]

I swear I checked them. But just in case I went and ordered a 644 relay... just in case.

I checked the relay like this. I applied 12v on the small pins (it clicked). While applying V on the small pins, I tested the big pins for continuity and the tester beeped, which means it's a closed circuit. Apart from that... I dunno another way to test them.

I HOPE it's the relay because I'm out of options and out of my depth if there's something else...

I promise you guys, I'm usually not this stupid

[Doc]

You have checked the vehicle is supplying 12V and ground to the coil of the relay as I suggested in an earlier post?

[Odo13tz]

I did! It was 6 or 8v if I remember correctly

[Doc]

That will be your problem!
This should be a 12V supply.

[Odo13tz]

Just measured it again. It's 12v. I must've remembered incorrectly.

In conclusion, it seems to be a bad relay. Hopefully I'll get the new one later today and I will confirm.

[petrev]

That's my guess too !

[Doc]

Sounds very plausible, if you have another 644 relay (Rear demister maybe) you could swap that into the position of the problematic relay to prove/disprove.

[Odo13tz]

It's not the relay. I just changed it with a brand new one. Below are the readings with and without the relay into the socket

Small pins with relay in



Big pins with relay in



Big pins relay out



Small pins relay out



I think my battery is getting a bit lower with all the try and fail that's why I get less than 12v on the small pins without the relay in.

Any idea what could cause this? It seemed such a good case of bad relay. Now I'm completely out of ideas.

[petrev]

Have you got the IGN On when you read across the signal small pins ?

IGN Off the signal + side is floating so not pulled to Batt+

[petrev]

Big Pins relay IN should be 0V as the relay should be closed. With IGN ON.

p.s. Where are you based ?

[Odo13tz]

Ignition was on.

I am in Braintree (Colchester) but will ing to travel if it's not too far it's cold outside and I have no heating

[petrev]

Too far from me

Something strange going on as it should be 0V across big Pins if the relay were closed properly - So it isn't !!

[Odo13tz]

Too far from me

Something strange going on as it should be 0V across big Pins if the relay were closed properly - So it isn't !!

If the relay clicks, it closes so it should brigade the gap, which means it should have voltage with ignition ON, but apparently the voltage drops on the small pins and it doesn't keep them closed...

[petrev]

Earth wire (brown) ?

Put a solid earth on the back of the relay carrier onto the brown wire.