DIYPNP, Fan not working after repair on board.

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ZenitramNaes
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DIYPNP, Fan not working after repair on board.

Post by ZenitramNaes »

Hello everyone.

Had my fan all wired up correctly and all the settings were correct in TS and worked perfect for months. I sent my unit away for an unrelated issue regarding the fuel pump switch, they cleaned up and replaced suspect wires and one of them was in the fan circuit, now the fan circuit is currently not working. Just trying to get to the bottom of it.

I've tested the fan and the fan works if I manually ground the switch going into ms, ms just isn't grounding it at the set temp.

I have 5volts going into relay 1 and 12 volts reaching relay 1 out coming from the fan relay outside of the ms.

Essentially the relay on the board just isn't tripping in order to ground that 12volts. What can I test in order to narrow down this issue?

Thank you very much!

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'89 535i/5 Holset WH1E turbo
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Blown88GT
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Re: DIYPNP, Fan not working after repair on board.

Post by Blown88GT »

I assume you did not build this yourself, i.e. not the original owner?
Who did you send it back to for repair? DIY AutoTune?
I suspect they rewired it to a different MS output.
If they did, you will have to modify the TS configuration.
Your sketch gives no useful information.
Can't get details from the pictures.
You're using the optional DB-15 for something, maybe the external fan relay?
Make a spreadsheet or a list showing the silkscreen label on each end of the wires.
With all the additional wiring, you'll have to figure it out.
Like this:
PE0 to Relay 1 In
etc.
etc.
1988 Mustang GT, 59k miles, Orig Owner
ProCharger 600B I/C, 12psi, FRP Hdrs, Flwmstr F2, 3G Alt, Contour Fan & DCC, 3.55's, Prog Sprg, Subfms, UCA, LCA, FCA, Tokico 5's, Bridgestone RE-71R 245/40R17, Crane HI-6, Kirban FPR, MS2, DIYPNPF60, Spartan 2, C&L76mm blo-thru MAF, 47lb FRP-LU47
ZenitramNaes
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Posts: 109
Joined: Sun Dec 15, 2013 2:35 pm
Location: Tallahassee, Florida

Re: DIYPNP, Fan not working after repair on board.

Post by ZenitramNaes »

Blown88GT wrote:I assume you did not build this yourself, i.e. not the original owner?
Who did you send it back to for repair? DIY AutoTune?
I suspect they rewired it to a different MS output.
If they did, you will have to modify the TS configuration.
Your sketch gives no useful information.
Can't get details from the pictures.
You're using the optional DB-15 for something, maybe the external fan relay?
Make a spreadsheet or a list showing the silkscreen label on each end of the wires.
With all the additional wiring, you'll have to figure it out.
Like this:
PE0 to Relay 1 In
etc.
etc.
No, I'm the original builder.
Sorry, should have been more specific about the wiring on the board. The guy who did the repairs (who is highly recommended) cleaned up some joints and replaced some wires, but nothing change other than that, everything is where it should be which makes this so perplexing. I'm thinking it's just more of a coincidence and nothing he did wrong.

PAO to relay 1 IN
relay 1 OUT to Db-14

None of the settings in TS have been changed. I've tried to force the fan on by lowering the required temp for the fan settings, still nothing. I have 12v coming in to the relay, but it seems that the relay on the board isn't grounding out the wire in order to switch on the fan.

My only idea is maybe replacing relay 1 with a new kit.
'89 535i/5 Holset WH1E turbo
Follow my m106 megasquirt build thread: http://forums.bimmerforums.com/forum/sh ... rt-content
Blown88GT
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Posts: 929
Joined: Sun Dec 15, 2013 7:53 pm
Location: South Florida

Re: DIYPNP, Fan not working after repair on board.

Post by Blown88GT »

ZenitramNaes wrote:...PAO to relay 1 IN
relay 1 OUT to Db-14
...I have 12v coming in to the relay, but it seems that the relay on the board isn't grounding out the wire in order to switch on the fan.
My only idea is maybe replacing relay 1 with a new kit.
The board doesn't have a relay, it's a transistor used as a switch. It is used to control the coil of an external mechanical relay.

What kind of e-fan & what kind of external relay? The 30 or 40A automotive relays will fail with most e-fans. The contacts burn up.
Relay coils generally only need 300ma to control them. Not a problem for the DIY, those transistors (Q6) are rated at 1A.
http://www.bcae1.com/relays.htm

Your wiring looks okay in the pics.
Do you have this for reference?
Microsquirt-Module_Developers_Guide-3.4.pdf

You said this:
PAO to relay 1 IN
PA0 is an output, it is connected directly to the MS Module.
You may have damaged the Module and/or Q6.
You're not using relay 2, try him.

Add this & add TS output port. Connect the external relay, but disconnect the fan & used a 12V lamp. You can hear the relay click, too.
PT6 to relay 2 IN
relay 2 OUT to Db-13

I used these circuits to control the A/C WOT relay.
1988 Mustang GT, 59k miles, Orig Owner
ProCharger 600B I/C, 12psi, FRP Hdrs, Flwmstr F2, 3G Alt, Contour Fan & DCC, 3.55's, Prog Sprg, Subfms, UCA, LCA, FCA, Tokico 5's, Bridgestone RE-71R 245/40R17, Crane HI-6, Kirban FPR, MS2, DIYPNPF60, Spartan 2, C&L76mm blo-thru MAF, 47lb FRP-LU47
ZenitramNaes
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Posts: 109
Joined: Sun Dec 15, 2013 2:35 pm
Location: Tallahassee, Florida

Re: DIYPNP, Fan not working after repair on board.

Post by ZenitramNaes »

Wanted to revisit this because trying to get the car 100% again.

I've replaced the relay 1 kit with no success, same issue. I've switched input from PA0 to PT6, no success.

I can physically ground the external fan relay and it will work fine. MS is sending out 12v and its unable to ground out the circuit when the on/off output thresolds are met.
'89 535i/5 Holset WH1E turbo
Follow my m106 megasquirt build thread: http://forums.bimmerforums.com/forum/sh ... rt-content
Matt Cramer
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Joined: Thu Apr 16, 2009 8:08 pm

Re: DIYPNP, Fan not working after repair on board.

Post by Matt Cramer »

Time to do some voltage checks using output test mode - I/O. With PA0 set to off, you should have 0 volts on the PA0 wire, and the relay output pin will have 12 volts with a relay or test light wired to it. With PA0 on, the PA0 wire should have 5 volts, and the relay circuit output should be grounded.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
ZenitramNaes
Helpful MS/Extra'er
Posts: 109
Joined: Sun Dec 15, 2013 2:35 pm
Location: Tallahassee, Florida

Re: DIYPNP, Fan not working after repair on board.

Post by ZenitramNaes »

Thanks for the reply Matt! Got ahold of Peter F and we talked through it, the 5v was making it to IN but not getting to the resistor so we concluded there was a broken trace somewhere in between. Moved to Relay 3 spot and all is good in the world.
'89 535i/5 Holset WH1E turbo
Follow my m106 megasquirt build thread: http://forums.bimmerforums.com/forum/sh ... rt-content
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