Questions & Answers

'07 Jeep GC, MUX voltage, key on- no crank, verifying wiring connections

+1 vote

2007 Jeep Grand Cherokee Diesel Automatic, EVO-CHRT5 T harness, standalone F diagram. 74.07 firmware, 6.0 hardware, Bypass checked "on"  are A1,3,7 C1, D1, D2, all other options are checked "off". OEM key programming was successful. When I push lock 3X the ingition comes on but engnine does not crank. I checked ignition connection after lock 3x, the power consant (white /blue) =12v and starter cranking (white/red) = 11.9v. The MUX voltage (VOM on green /red and chassis ground)  with no key =4.19v, key in=3.61v, key on=.993v, crank =.36v.... when remote starting "key on" =1.05v, "key off"=4.19v, cranking = .40V. .. I also have error codes/warnings ( trans temp, 4WD system fault) that appear on dash when it tries to remote start.  I have attached pic of wiring to the ingnition connection. I'm questioning MUX voltage and correct wiring? attached pics. the wires are soldered to pins in connector

asked Jan 9, 2019 in Jeep by Brent Blunier (160 points)
edited Jan 31, 2019 by Brent Blunier

2 Answers

+2 votes
Did you only insert wire into cavity ?

If yes, this is NOT a good connection, you must remove insulation from the wires and connect directly.
answered Jan 9, 2019 by Mathieu Bertrand Collin (62,040 points)
as mentioned in the description above- I pulled pin out of connector, stripped and soldered the Forstin wires to the pins, reinserted the pin. I think I have good connection.
MUX voltage seems good.

What voltage on white/blue when remote starting ?
I have tested the white/ blue for dropping voltage during remote start and it stay around 12v all the time. I will check again to be sure... I am glad the MUX volage are good, that was one of my concerns, I don't know what they should be. ....My other concern is the dash shows "Trans Temp", "Service 4WD system", "check gauges" while trying to remote start. This leads me to think there is a CAN BUS problem from module. Is it possible i have a bad EVO-ALL?
Found Problem- Wiring error, my fault...After cutting the yellow/red, I mistakenly connected the yellow/red from T harness to ignition.... I needed to connect the yellow/red from the Red connector on module to the ignition. After doing that , everything worked. Forstin has great support and great product.
hello, sorry to dig up an old thread... im trying to install a repmote start on my Grand Ckerokee 2007.

the porblem im having is down to the MUx wire. any help you can provide would be great.

 

I have it conencted through a 560ohm resistore through ground and when the remote starts, I gett he warning errors that you described, trans temp etc.

 

If I remote start without this conencted, it works but I haev no gauges or Blowers etc.

 

Im not a novice but this is frying my brain, any adice woudl be greatly appreciated.
why do you have a resistor on the mux wire? it's a straight connection between evo and car
Hi, thanks for the reply, I dint realise I was replying to a specific thread about an evo?!?

 

I am installing an aftermarket push and remote start - apparenlty the MUX on a Jepp is sensitive and required the MUX lead to be eartherd through a 560 resistor for ACC and through a 150 resistor for the 2nd start funciton.

 

Now, I have done this usign relays etc, it all works, remotre start etc, except I egt the check gaugues, check transmission temp, check 4WD erros as menitoned in this thread - its doiny my head in, I can only assume the infomraiton im using is incorrect and it needs a different value than 560 ohms but htere are bout 15 sources I've found that say 560ohm - Im far from a novice when it ocmes to autoelextrics but this one has stumped me.

I havent even started with the negative trigger, single wire lock/unlock which also requires relays and resisters but thats another day, I want to get the remote start working first
The green/red of the evo already supplies the proper value for crank.
im not using an evo, not sure what that even is, its a generic aftermarket push button/remote start, installed 3 or 4 of them in teh past, the touble im having is getting the MUX to recognise ignition on, withouth causing all the errors.

 

normally its a simple case of connecting the ACC out of the starter unit to the ACC wire beding the ignition, but eith the mux cable, there is a specific voltage/resistance which I canot seam to find.
0 votes
I had a problem with mine too and what it ended up being was the picture of the clip you tie into looks like the front but in small letters says it's the back so I had my wires soldered in reverse. Not sure if this helps.
answered Jan 21, 2019 by Rylee Stevens (230 points)
Found Problem- Wiring error, my fault...After cutting the yellow/red, I mistakenly connected the yellow/red from T harness to ignition.... I needed to connect the yellow/red from the Red connector on module to the ignition. After doing that , everything worked. Forstin has great support and great product.
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