I have a bit of an electrical problem here. This is not in a Honda (it is my Saab), but I am rather helpless right now. Let's say I have a relay that turns another one on. Since this is a Bosch relay, it looks like this:


86 and 85 are the pins for the relay coil (85 is ground and 86 is 12V) while 30 is 12V from the battery all the time and 87 is what pin 30 will be connected when you enable the relay. In relay 1, 86 is powered all the time; you close it by grounding 85. 87 in relay 1 is connected to 86 in relay 2. So, when relay 1 is closed, it powers the pin 86 in relay 2. Now, relay 2 is enabled by also ground its pin 85:



There is a (boost) pressure switch between the two relays, probably to turn the second relay off if there is too much boost. In any case, I manually turn relay 1 by grounding its pin 85 and do check that pin 86 in relay 2 now has 12v. Then I try to turn relay 2 by grounding its pin 85 and check voltage in pin 87. Nothing. What does that mean? Is something eating up the current so there is not much left to turn relay 2 on?

 

On relay 2, if you have current through pin 86 when grounded (make sure its getting grounded correctly and the current is the same out of relay 1 and into relay 2), check to see if there is voltage at pin 30 (maybe the wire from the battery is open). If there is voltage and no current, then your relay is internally broken. Whack it a few times with a stick.

 

What would be a good way to check the current? I did check the pin 30 on relay 2 and it does give me 12V. I also tried to use a different switch and it did not work. This is annoying the hell out of me, specially since those relays are in a location almost as bad as the ones in my 87 Integra.

 

Some ideas:

Put a multimeter in series with pin 87 and the pressure switch and compare it with the current after the pressure switch. Maybe that switch is shorting on something.

For troubleshooting purposes you could run a wire from pin 87 to pin 86 to eliminate the pressure switch all together and proceed to retest the setup.

But from you saying that there is voltage at pin 86 and 30 on relay 2 and the relay just wont throw when grounded. I would check the ground wire to make sure it isn't open somewhere.

Could that pressure switch provide a path to ground for relay 2? What does the schematic look like for it?