ALH Glow Plug Light Wiring

[libbybapa]

I have done a fair amount of searching and reading and have been unable to come up with the needed info.

I am working on a Vanagon that was converted to an ALH (I was told it is an '02) with the electronic engine management and the Mk4 instrument cluster. The conversion was not done by me so trying to sort it is somewhat frustrating. The glow plug light is currently not working. It does not turn on when the key is turned to the ON position. I have been unable to even find the glow plug light listed in the Bentley wiring diagrams for the instrument cluster wiring. Bentley 90-6 Instruments gives the pins for the two 32-pin connectors for the instrument cluster and shows the glow plug light (K29) as pin 13 on T32 blue but does not give any wiring colors for the bundle of wires.

Does anyone know what wire color that would be? Is that supposed to run to the ECU where the ECU grounds it to turn on the glow plug light? If so, which pin on the ECU should that run to?

Any help is appreciated.

 

[jimbote]

Hey Andrew, there is no dedicated glow wire from the ecm to the cluster on an ALH 121 pin ecm as it's handled via can so you'll need to improvise if not using an ALH cluster. Pin 40 long plug on the 121 edc15 is where I sourced my glow indicator and it works great. I have it powering a 1watt? bulb and it's been trouble free for nearly ten years and over 170k miles. And yes, this circuit does ground the bulb, so 12v on vehicle side of indicator and pin 40 to the other and you'll be golden.

Toyota Tacoma ALH Swaparoo!!

This is my first attempted TDI conversion although I've been cerebralizing on it for several years...I've had several toyota trucks that I was "going to convert" but none felt right for the swap...so here it is, a 96' tacoma X-Cab 4x4 I found on craig's list greensboro...it was "dinged" in the...

forums.tdiclub.com

 

[libbybapa]

decided to post this so all the info is in one place within this thread... i'll update with more info as time allows
121 ecm interface pin/wire chart:
component:...........pin color
CEL:…...................24 ws/bl
tach:.....................27 gn/br
glow:.....................40 bl/gn
vss:.......................20 bl/ws
k line:....................16 gr/ws
clutch cancel n/c:..........66 ws/ro
BS n/o:...................32 ro/sw (grounded or lamp side of brake switch)
BS n/c:...................65 ws/ge
"wake up"
(key O/S):...............37 sw/li

hope this helps

this is to correct the reversed function of the cel when using pin 24 as the source ...credit goes to Alchemist for designing this circuit
emitter>ground
base>switched 12v THROUGH resistor plus ecm pin 24
collector>negative side of CEL

Thanks for the reply. To be clear, pin 40 bl/gn is for the glow plug light (and not for the actual glow plugs)? Does the light get power from within the cluster and then then the ECU connects pin 40 to ground to turn the glow plug light on?

I don't understand the pic. You say it is to correct the CEL but the hand-drawn image on the rightmost wire is the glow plug icon rather than CEL.

 

[jimbote]

Thanks for the reply. To be clear, pin 40 bl/gn is for the glow plug light (and not for the actual glow plugs)? Does the light get power from within the cluster and then then the ECU connects pin 40 to ground to turn the glow plug light on?

I don't understand the pic. You say it is to correct the CEL but the hand-drawn image on the rightmost wire is the glow plug icon rather than CEL.

You can ignore the pic if you're not using a cel in your swap. The page link was so you could see the necessary pinouts for most swaps including the glow. Pin 40, among others,as far as i can tell, on the ecm is a vestigial output for applications outside the mkiv platform. So it still functions as a glow light indicator but is not used as such in the mark4 cars. The mk4 cluster is NOT required for the cel, glow, or tach outputs present on the 121 pin ecm's. Now from what I've heard some later 121 ecm's may not have active outputs on these pins. As for the "glow" symbol it's supposed to represent a bulb so I can see where that might be confusing. Yes, power is provided on the vehicle (cluster) side of the bulb and ground is provided by the ecm.

 

[libbybapa]

The van I'm working on is using the ALH cluster but the glow plug light does not ever come on. I'm trying to determine if that is a fault with the cluster or wiring. I was not the one who performed the swap and do not have contact with the person who did. I'm not looking to get a glow plug light working on a different cluster, just trying to diagnose what is currently there.

 

[jimbote]

The van I'm working on is using the ALH cluster but the glow plug light does not ever come on. I'm trying to determine if that is a fault with the cluster or wiring. I was not the one who performed the swap and do not have contact with the person who did. I'm not looking to get a glow plug light working on a different cluster, just trying to diagnose what is currently there.

are the CAN wires connected? And are you sure it's a TDI cluster?

 

[jimbote]

it may also pass the info via the k line but I have not tried this. And sorry Andrew, I should have read your post more carefully.

 

[libbybapa]

I'm sure it is using the Mk4 cluster. I'm not sure of the status of the CAN or K-line connections. I'll look into that. Thanks again.