Spare Ports stopped working

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AndyB400
MegaSquirt Newbie
Posts: 3
Joined: Sat Dec 06, 2014 1:14 am

Spare Ports stopped working

Post by AndyB400 »

Hi, I've been running my 4.0 V8 with EDIS for 2 years now and it's been working great. Recently I've run into some issues, my spare ports are setup as below but Accel and Warmup outputs no longer work. The relays stopped operating so I checked them with a multimeter and they just read milli volts all the time. They voltages do flinch when the operating condition is met but it's 10mV to 20mV. I'm guessing the transistors or chip is damaged. Is there any more diagnosis I can do? Is it a shared chip that does both these outputs? Tach out is still fine.

Tach Out: Shift light
Accel: Fan relay
Warmup: Water injection relay
Matt Cramer
Super Squirter
Posts: 910
Joined: Sat Jul 03, 2004 11:35 am

Re: Spare Ports stopped working

Post by Matt Cramer »

This sounds like the relays aren't getting their 12 volt supply voltage if they are off but you have 0V on the MicroSquirt.
Matt Cramer at DIY Autotune
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AndyB400
MegaSquirt Newbie
Posts: 3
Joined: Sat Dec 06, 2014 1:14 am

Re: Spare Ports stopped working

Post by AndyB400 »

Thanks for replying Matt, I'm testing it with nothing connected to ALED & WLED wires but the multimeter. So when checking the voltages that I get on ALED & WLED is always zero. I've spoke to James M regarding it and he suggested if it is a hardware fault I could check the voltage at the chip. Hopefully that should show if its the processor output is not working or the MOSFETs at fault.
AndyB400
MegaSquirt Newbie
Posts: 3
Joined: Sat Dec 06, 2014 1:14 am

Re: Spare Ports stopped working

Post by AndyB400 »

I've just gone back and done some reading around MOSFETs, it's all working properly now. I was expecting a voltage output rather a switched ground.
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