RESOVLED. For the "TLDR" folks looking for ARB/IPF Relay Part Numbers - here are two from Hella:
Hella 931680011 - Sealed Unit, Changeover Relay - Harness Requires 1. Replaced ProQuip P2512X
Hella 007791011 - Non-Sealed, Normally Open 4-prong relay (we will see how long they last). Harness Requires 2. Replaced ProQuip P1512X
Hi Everyone,
A couple of weeks ago while troubleshooting an electrical issue, I lost my low beam headlights. I'd put a substantial drain on the battery, but not enough that I couldn't start the FJ40. Oddly enough, after running the engine for a few minutes (presumably charging the battery a little) the headlights miraculously decided to start working again. So I just let it lie. I'm aware NONE of what I just wrote makes any sense from an electrical standpoint. Fast forward to yesterday - I just pulled the dash, put in a new speedometer cable, and replaced my dashboard lights with LED's. I also put a new LED in my headlight switch. I put everything back together, and once again, I have no low beams. This time, it doesn't seem like they're coming back on their own.
I found this post and have been trying to troubleshoot, but I'm sort of at a loss: Pull head light switch '78 FJ40
Based on the chart below I have taken a look at the voltage across the steering column switch terminal per figure 12-12. The "HL" terminal has 12V when the headlight switch is in the second position, so I believe I have proper low beam voltage.
HOWEVER, if I push the stalk forward to activate high beams, I don't see the voltage "swtich" to HU, but I'm not sure I'm supposed to?
To further confound things, I also have the IPF harness, and H4 headlights. The IPF harness makes use of 3 relays before it goes to the headlights, so I'm wondering if one of the relays went bad. Is there a good way to directly test a relay? I'm not entirely sure where to go from here.
To summarize Diagnostics so far:
- I have parking lights in the first pull position of the headlight switch. I also have functional dash and dimmer (lights get dimmer/brighter when I rotate the headlight switch.
- In the second pull position (switch all the way out) I have no low beams. BUT if I push the stalk forward, the high beams activate as they should.
- Confirmed 12V switched voltage from headlight switch on terminal HL, above. Neither HD nor HU appear to have voltage regardless of position but I may not be looking in the right place.
- Confirmed I have a full 12V power to the correct terminals at the end of the OEM headlight harness - ie: when I have low beams on, I have 12V at one terminal, if I switch to high beams, I have 12V at the other terminal.
- Grounds are shared between high and low beam and most of the grounds have been repaired/upgraded in the last couple years, so I don't expect there's an issue there.
- Both low beam filaments are intact, the bulbs aren't burned out.
So everything seems to work as it should, minus the low beams, and it seems like everything on the OEM (non-IPF side) is getting 12V as it should. That said, I accidentally plugged the IPF harness back in while the headlights were still "on" and I can hear at least one relay move.
This seems to point to the IPF harness or one of the relays, does it not? I'm not entirely sure how to check a relay for functionality or appropriate voltages. Any tips here? More importantly - does IPF sell replacement relays if this one is bad? Is there a better relay manufacturer I should be considering as a better replacement?
Hella 931680011 - Sealed Unit, Changeover Relay - Harness Requires 1. Replaced ProQuip P2512X
Hella 007791011 - Non-Sealed, Normally Open 4-prong relay (we will see how long they last). Harness Requires 2. Replaced ProQuip P1512X
Hi Everyone,
A couple of weeks ago while troubleshooting an electrical issue, I lost my low beam headlights. I'd put a substantial drain on the battery, but not enough that I couldn't start the FJ40. Oddly enough, after running the engine for a few minutes (presumably charging the battery a little) the headlights miraculously decided to start working again. So I just let it lie. I'm aware NONE of what I just wrote makes any sense from an electrical standpoint. Fast forward to yesterday - I just pulled the dash, put in a new speedometer cable, and replaced my dashboard lights with LED's. I also put a new LED in my headlight switch. I put everything back together, and once again, I have no low beams. This time, it doesn't seem like they're coming back on their own.
I found this post and have been trying to troubleshoot, but I'm sort of at a loss: Pull head light switch '78 FJ40
Based on the chart below I have taken a look at the voltage across the steering column switch terminal per figure 12-12. The "HL" terminal has 12V when the headlight switch is in the second position, so I believe I have proper low beam voltage.
HOWEVER, if I push the stalk forward to activate high beams, I don't see the voltage "swtich" to HU, but I'm not sure I'm supposed to?
To further confound things, I also have the IPF harness, and H4 headlights. The IPF harness makes use of 3 relays before it goes to the headlights, so I'm wondering if one of the relays went bad. Is there a good way to directly test a relay? I'm not entirely sure where to go from here.
To summarize Diagnostics so far:
- I have parking lights in the first pull position of the headlight switch. I also have functional dash and dimmer (lights get dimmer/brighter when I rotate the headlight switch.
- In the second pull position (switch all the way out) I have no low beams. BUT if I push the stalk forward, the high beams activate as they should.
- Confirmed 12V switched voltage from headlight switch on terminal HL, above. Neither HD nor HU appear to have voltage regardless of position but I may not be looking in the right place.
- Confirmed I have a full 12V power to the correct terminals at the end of the OEM headlight harness - ie: when I have low beams on, I have 12V at one terminal, if I switch to high beams, I have 12V at the other terminal.
- Grounds are shared between high and low beam and most of the grounds have been repaired/upgraded in the last couple years, so I don't expect there's an issue there.
- Both low beam filaments are intact, the bulbs aren't burned out.
So everything seems to work as it should, minus the low beams, and it seems like everything on the OEM (non-IPF side) is getting 12V as it should. That said, I accidentally plugged the IPF harness back in while the headlights were still "on" and I can hear at least one relay move.
This seems to point to the IPF harness or one of the relays, does it not? I'm not entirely sure how to check a relay for functionality or appropriate voltages. Any tips here? More importantly - does IPF sell replacement relays if this one is bad? Is there a better relay manufacturer I should be considering as a better replacement?
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