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Relay problem (home brew intercooler spray)

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=2802
Printed Date: August 09, 2025 at 6:22 PM


Topic: Relay problem (home brew intercooler spray)

Posted By: Jewbaru
Subject: Relay problem (home brew intercooler spray)
Date Posted: August 15, 2002 at 10:37 AM

Ok, I read the thread about the guy who was having horn troubles (converting positive to negative), considering I'm having a similar problem, however, it just made me even more stumped.

I have a turbocharged car, and using the factory washer pump, I fabricated an Intercooler spray for my top mount IC. I origionally used a 12v signal to turn on the pump, and gave the pump a good ground (which blew wiper fuses), but realized the pump is activated by a ground switch. So, I purchased a new relay, and moved the wires around. The setup is as follows.

30: Out to washer pump

87a: In from factory harness

87: Good ground

86: Good ground

85: 12v switched power.

Now, when I use the wipers, and stock spray button, everything works as normal, pump clicks on as well. However, when I flick the waterspray switch, just the wipers turn on, no pump! The relay is a Bosch relay, and I'm wondering if it's broken, or maybe I missed something. Anyhelp would be greatly appriciated.

P.S. Forgive my poor formatting, not used to this style BB. :)




Replies:

Posted By: Zeroc
Date Posted: August 22, 2002 at 2:20 AM

If everything is working alright normally, check to make sure that the realy that you wired in switches when you turn on the 12V switched power.

From what you have said here it seems as if the relay isn't switching on. You might want to check your 12V switched power.






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