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Topic: Starter Issue, HELP (Read 1155 times) previous topic - next topic

Re: Starter Issue, HELP

Reply #20 –
Why replace ignition until after checking circuits with meter. If ignition start wire still has 12v after ignition key is moved back from start position, then ignition switch is bad. If no 12v, ignition switch is NOT the problem.

Meter Aux Start solenoid: If starter motor is turning with NO voltage on cable to starter, then it is a starter problem.

Only replace parts after checking circuit with volt meter.

Re: Starter Issue, HELP

Reply #21 –
Possible isolator panel starter solenoid is sticking closed and not releasing, something to check.

Re: Starter Issue, HELP

Reply #22 –
Another ignition key to starter wiring sequence for our coach:
 
wire

circuit  code        description

START BATTERY

B1 000 start battery POS post big cable goes to starter solenoid large terminal

B5 000 start battery NEG post new very big cable bolted to motorhome frame [change to bolt to engine]

STARTER

B5 000 big cable from battery to starter solenoid large terminal

B14 2RD            big cable on start solenoid goes to rightmost isolator terminal

ISOLATOR

B14 2RD            big cable from starter solenoid

B15 2RD            large cable to 90-amp circuit breaker on bay wall panel

B26 RD wire to aux start solenoid on isolator panel aux start solenoid

BAY WALL PANEL BREAKER

B15 2RD            large cable from isolator to leftmost 90-amp big round start battery circuit breaker's lower terminal

B69      wire from 90-amp breaker to 30-amp ATEC circuit breaker on bay wall panel

C6 RD  10-gauge wire from 30-amp ATEC breaker to front door panel

FRONT DOOR PANEL BREAKER

C6 RD  wire from bay wall panel to leftmost 10-amp ATEC-ECM circuit breaker located on top-row

136 WH wire from 10-amp breaker to Allison ECM interface-plug RD# 136A & 136C, "unswitched batt +"

ALLISON ECM COMPUTER

ECM computer is located behind carpeted side panel to the left of driver's left foot

136 WH wire from 10-amp breaker to both terminals RD# 136A & 136C, labeled "unswitched batt +"

123 PU wire from ECM terminal PU# 123, labeled "neutral safety", indicating transmission is in neutral, to neutral safety relay

FRONT DOOR PANEL RELAY

123 PU 12-volt positive from Allison, when transmission is in neutral will close #86 coil on neutral safety relay

green    ground wire completes #85 coil circuit on neutral safety relay located 2nd from bottom on right side of panel

122 WH ignition key momentary start position flows start battery current to neutral start relay #30 common terminal

E9 WH  ignition key current flows from N/O #87 relay terminal to aux start solenoid located on isolator panel

ISOLATOR PANEL SOLENOID

AUX START solenoid is leftmost of the two solenoids and is located in center of isolator panel above air cleaner

E9 WH  ignition key current flows through neutral start relay to small coil terminal on the aux start solenoid, coil is internally grounded to case

B26 RD start battery current flows from isolator terminal through aux start solenoid when solenoid is closed (by ignition momentary start)

B25 RD when aux start solenoid is closed start battery current flow to starter solenoid coil to activate engine starter, coil is internally grounded

IGNITION RELAYS

IGNITION DUAL-RELAYS are large cube-shaped and are mounted to lower center of front door panel

REMOTE STOP RELAY is positioned lying loose in bottom center of front door panel

103 WH when ignition key is turned on, 103 WH flows start battery current through secure-switch to

remote-stop relay #30 common terminal and through NORMALLY-CLOSED #87A terminal

103A WH              to dual-ignition-solenoid coils to close ignition relays, which allows start battery current to flow to ALL ignition circuits

REAR ENGINE REMOTE START PANEL

E21 WH ignition circuit breaker #19 located in front door panel powers remote start system start & stop momentary push button switches

E23 WH pushing remote start switch powers ignition key start wire E22-WH to turn starter on (same as turning ignition key to start positon)

E61 WH pushing remote stop switch powers remote stop relay #86 coil, opening relay and turning 103A-WH power off to ignition dual-relays

green    ground wire completes #85 coil circuit on remote stop relay

when remote stop relay is powered, 103A-WH power from ignition key is disrupted, turning off ALL ignition circuits MOMENTARILY,

which kills power to engine fuel shut-off solenoid, thus stopping engine

letting up on remote stop switch allows ignition dual-relays to again close, as ignition key is still on

Re: Starter Issue, HELP

Reply #23 –
There are several actuation steps that occur in sequence when our ignition key is turned to "start" position:

starter engage circuit from wiring diagram



start battery cable connections

1            Start battery positive post

2                          starter solenoid terminal

3                          to boost solenoid terminal

4                                          isolator terminal

5                                          to 90 amp circuit breaker terminal (behind white bay wall panel)

30 amp Allison circuit breaker (behind white bay wall panel)

6                          input B69

7                          output C6 red

10 amp Allison circuit breaker #1 (right-dash panel)

8                          input ATEC-ECM C6 red

9                          output ATEC-ECM 136 white

Allison transmission ECM (behind lower left driver seat side kick panel

10                        inputs B2-136A & B11-136C - unswitched battery +

11                        output A23-123 PU Violet - neutral-start output when trans in neutral (closes relay #1 coil)

ignition switch

12                        input 91 white from 15 amp circuit breaker #28 (located on front dash breaker panel start batt buss)

13                        output 122 white start position to neutral safety relay common

neutral safety bosch relay R1 (right side of front dash CB panel)

14                        relay 86 coil from step#11 (trans neutral closes relay) 123 purple

15                        relay 85 coil (battery negative connected to other coil terminal)

16                        relay 30 common is from ignition switch start position 122 white step#13 (or from remote start button E23)

17                        relay 87 N/O is E9 white to aux start solenoid coil (powered from ignition switch start) on isolator panel

(aux start sol below closes when when trans in neutral & ign key in start position)

(and aux start solenoid coil is powered from ignition key start position)

auxilary start solenoid (located on inverter panel)

18                        coil small wire from step#17 (battery positive closes relay)

19                        input large side post from start battery positive step#4 B26 red

20                        output large side post to starter solenoid coil B25 red

Re: Starter Issue, HELP

Reply #24 –
IF there is there 12v on large output terminal when there are zero volts on small terminal(S) it is sticking OR the starter solenoid is backfeeding 12v from big wire to starter.

Check Aux Start solenoid by removing the output cable on the large solenoid terminal. If still 12v on large threaded bolt terminal it is sticking.

Re: Starter Issue, HELP

Reply #25 –
Quote from: craneman –
Disconnect the starter button at the rear of the coach and try again.

Problem solved!! I removed one of the wires from the start button and checked the small solenoid wire for proper power, fixed.

Looking back, I did not need to change the ignition ($32 cheap enough)  but it was a learning experience. Due to the problem, it was good to get the starter rebuilt.

Thank you for everyone's help!!